Filtration media pack, filter element, and methods

ABSTRACT

A filtration media pack is provided having a plurality of layers of single facer media. The layer of single facer media includes a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet and having a flute length extending from a first face to a second face of the filtration media pack. A first portion of the plurality of flutes are closed to unfiltered fluid flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes are closed to unfiltered fluid flowing out of the second portion of the plurality of flutes so that fluid passing into one of the first face and the second face of the media pack and out the other face of the media pack passes through media to provide filtration of the fluid.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/221,824, filed Jul. 28, 2016, which is a continuation of U.S.application Ser. No. 14/040,929, filed Sep. 30, 2013, now U.S. Pat. No.9,433,884, issued Sep. 6, 2016, which is a continuation of U.S.application Ser. No. 12/215,718, filed Jun. 26, 2008, now U.S. Pat. No.8,545,589, issued Oct. 1, 2013, which claims the benefit of U.S.Provisional Application No. 60/937,162, filed Jun. 26, 2007, thecontents of which are herein incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a filtration media pack and a filterelement that can be used to filter a fluid. The invention isadditionally directed to methods for manufacturing and using afiltration media pack.

BACKGROUND

Fluid streams, such as air and liquid, carry contaminant materialtherein. In many instances, it is desired to filter some or all of thecontaminant materials from the fluid stream. For example, air flowstreams to engines for motorized vehicles or for power generationequipment, gas streams to gas turbine systems, and air streams tovarious combustion furnaces, carry particulate contaminants therein thatshould be filtered. Also liquid streams in engine lube systems,hydraulic systems, coolant systems or fuel systems, can carrycontaminants that should be filtered. It is preferred for such systems,that selected contaminant material be removed from (or have its levelreduced in) the fluid. A variety of fluid filter (air or liquid filter)arrangements have been developed for contaminant reduction. In general,however, continued improvements are sought.

Z-media generally refers to a type of fluted filtering media elementwhere a fluid enters flutes on a first face of the media element andexits from flutes at a second face of the media element. In general, thefaces on z-media are provided on opposite ends of the media. The fluidenters through open flutes on one face and exits through open flutes onthe other face. At some point between the first face and the secondface, the fluid passes from one flute to another flute to provide forfiltration.

Early forms of z-media were often referred to as corrugated mediabecause the characterization of the media was adopted from thecorrugated box board industry. Corrugated box boards, however, weregenerally designed for carrying a load. Accordingly, flute designs canbe modified away from the standards and sizes from the corrugated boxboard industry to provide improved filtration media performance.

Various disclosures have been provided for modifying the form of theflutes in z-media. For example, U.S. Pat. No. 5,562,825 describescorrugation patterns which utilize somewhat semicircular (in crosssection) inlet flutes adjacent narrow V-shaped (with curved sides) exitflutes are shown (see FIGS. 1 and 3, of U.S. Pat. No. 5,562,825). InU.S. Pat. No. 5,049,326 to Matsumoto et al., circular (in cross-section)or tubular flutes defined by one sheet having half tubes attached toanother sheet having half tubes, with flat regions between the resultingparallel, straight, flutes are shown. See FIG. 2 of U.S. Pat. No.5,049,326. U.S. Pat. No. 4,925,561 to Ishii et al. (FIG. 1) shows flutesfolded to have a rectangular cross section, in which the flutes taperalong their lengths. In WO 97/40918 (FIG. 1), flutes or parallelcorrugations which have a curved, wave patterns (from adjacent curvedconvex and concave troughs) but which taper along their lengths (andthus are not straight) are shown. Also, in WO 97/40918 flutes which havecurved wave patterns, but with different sized ridges and troughs, areshown.

SUMMARY

A filtration media pack is provided according to the present invention.The filtration media pack includes a plurality of layers of single facermedia. A layer of single facer media comprises a fluted sheet, a facingsheet, and a plurality of flutes extending between the fluted sheet andthe facing sheet and having a flute length extending from a first faceof the filtration media pack to a second face of the filtration mediapack. The filtration media pack includes a first portion of flutes thatare closed to unfiltered fluid flowing into the first portion of theflutes and a second portion of flutes that are closed to unfilteredfluid flowing out of the second portion of the flutes so that fluidpassing into one of the first face or the second face of the media packand out the other of the first face or the second face of the media packpasses through media to provide filtration of the fluid. The filtrationmedia pack can be characterized as a z-media pack, if desired, and canbe provided having inlet flutes and outlet flutes so that unfilteredfluid flows into the media pack via the inlet flutes and out of themedia pack via the outlet flutes. It should be understood, however, thatthe flutes of the media pack need not be characterized as inlet flutesand outlet flutes.

The performance of the filtration media pack can be altered or modifiedby selecting from several design criteria. The term “performance”generally refers to at least one of increased longevity, increasedloading capacity, decreased pressure drop, increased flow, decreasedsize or volume, etc. For example, the filtration media pack can bedesigned for a particular application to provide enhanced performancecompared with certain presently available z-media packs. Enhancingperformance can result from, for example, controlling one or more ofmasking, flute width height ratio, flute length, flute density, fluteshape, reducing plug length, flute taper, and flute volume asymmetry.Any of these techniques can be used alone or in combination to provide afiltration media pack having desired properties.

The Applicants have found that the extent of performance improvement ofa filtration media pack increases as additional design characteristicsof the media pack are controlled. For example, the performance of amedia pack can be improved relative to a standard media pack from, forexample, standard B flute media, by adjusting a single design criteriasuch as masking, flute width height ratio, flute length, flute density,flute shape, plug length, flute taper, and flute volume asymmetry. Inaddition, the Applicants have found that enhanced performance can beprovided as a result of controlling an additional design criteria.

In an embodiment, the filtration media pack can be controlled to have aplurality of flutes having an average flute length of less than 5inches, and can be controlled so that the filtration media pack exhibitsa flute density (p) of at least 35.0 flute/inch² according to theformula:

$\rho = \frac{\text{number~~of~~channels~~(open~~and~~closed)}}{2 \times z\text{-media~~pack~~cross sectional~~area}}$

wherein the number of channels is counted and the media cross sectionalarea is measured. In addition, the filtration media pack can exhibit atleast one of:

(i) at least one of the first portion of the plurality of flutes or thesecond portion of the plurality of flutes are closed as a result ofplugs having an average plug length of less than 7 mm;

(ii) a flute width height ratio of greater than 2.5; or

(iii) a flute width height ration of less than 0.4.

In an alternative embodiment of the filtration media pack, thefiltration media pack can be provided exhibiting a flute density of atleast 35.0 flute/inch², and can have an asymmetric volume arrangement sothat a volume on one side of the media pack is greater than a volume onanother side of the media pack by at least 10%.

In another alternative arrangement for the filtration media pack, thefiltration media pack can have an average flute length of greater thanabout 4 inches, a flute width height ratio of greater than to 2.5 orless than 0.4, and an asymmetric volume arrangement so that the volumeon one side of the media pack is greater than a volume on the other sideof the media pack by at least 10%.

In another alternative filtration media pack according to the presentinvention, the filtration media pack can have an average flute length ofgreater than about 8 inches, a flute width height ratio of greater than2.5 or a flute width height ratio of less than 0.4, and a non-asymmetricvolume arrangement so that a volume on one side of the media pack is notgreater than the volume on the other side of the media pack by, morethan at least 100%.

The performance the filtration media pack can be improved by controllingthe shape of the flutes. For example, the fluted media can have a singleridge extending along at least a portion of the flute between adjacentpeaks. This flute shape can be referred to as “low contact.” The flutedsheet can include two ridges extending along at least a portion of thelength of the flute between adjacent peaks. This shape of the flute canbe referred to as “zero strain” or “Y” shaped. The fluted sheet can beconstructed to provide a repeating pattern of one, two, or more ridgesextending along at least 50% of the fluted length between an internalpeak and an external peak. The repeating pattern can be provided betweenall adjacent peaks or between some repeating pattern that is less thanall repeating peaks such as between every other repeating peak, betweenevery third repeating peak, between every fourth repeating peak, etc.Portions of the fluted media need not include ridges extending betweenadjacent peaks.

Filter elements can be provided that includes the filtration media pack.The filter element includes a seal member extending around a peripheryof the media pack. The seal member can include a seal surfaceconstructed to engage a housing surface in a radially extendingdirection to provide a seal. Alternatively, the seal member can includea seal surface constructed to engage a housing surface in an axiallyextending direction to provide a seal. The seal member can be attacheddirectly to the media pack or attached indirectly (via another structuresuch as a seal support) to the media pack

Methods for manufacturing a filtration media pack are provided. Themethod can include stacking or rolling a plurality of layers of singlefacer media to form the filtration media pack.

Methods for filtering a fluid are provided. The method can includefeeding a fluid to one of a first face or a second face of a filtrationmedia pack, and recovering fluid from the other of the first face or thesecond face of the filtration media pack.

The fluid that can be filtered by the filtration media pack includesgaseous substances and liquid substances. Exemplary gaseous substancesthat can be filtered includes air. Exemplary liquid substances that canbe filtered include water, oil, fuel, and hydraulic fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, schematic, perspective view of an exemplaryz-filtration media according to the prior art.

FIG. 2 is an enlarged schematic, cross-sectional view of a portion ofthe prior art media depicted in FIG. 1.

FIGS. 3A-3G are schematic views of various corrugated media definitions.

FIGS. 4A-C are enlarged schematic, cross-sectional views of a portion ofmedia illustrating width height ratio.

FIGS. 5A-C are enlarged schematic, cross-sectional views of a portion ofmedia according to the present invention.

FIG. 6 is a photograph showing an end view of wound filtration mediaaccording to FIG. 5A.

FIG. 7 is a photograph showing a perspective view of dust loaded intothe filtration media shown in FIG. 6 wherein a portion of the flutedsheet is peeled back to reveal a dust cake.

FIG. 8 is a perspective view of a tapered fluted sheet of the mediaaccording to FIG. 5B.

FIGS. 9A, 9B′, 9B″, and 9B′″ are sectional views of a tapered mediaaccording to FIGS. 5B and 5C.

FIGS. 10A and 10B are enlarged schematic, cross-sectional views of aportion of volume asymmetric media according to the present invention.

FIG. 11 is a cross-sectional view of a flute after contact with aninverter wheel and before contact with a folder wheel for closure of theflute.

FIG. 12 is a cross-sectional view of a flute taken along line 12-12 ofFIG. 11.

FIG. 13 is a cross-sectional view of a flute taken along line 13-13 ofFIG. 11.

FIG. 14 is a cross-sectional view of a flute after contact with a folderwheel.

FIG. 15 is a cross-sectional view of a flute taken alone line 15-15 ofFIG. 14.

FIG. 16 is a cross-sectional view of a flute taken along line 16-16 ofFIG. 14.

FIG. 17 is a cross-sectional view of a flute taken along line 17-17 ofFIG. 14.

FIG. 18 is an end view of a folded flute depicted in FIG. 14.

FIG. 19 is a sectional view of an exemplary air cleaner that can includea filter element containing the filtration media pack according to thepresent invention.

FIG. 20 is a partial, sectional view of a filter element containing afiltration media pack according to the present invention.

FIG. 21 is a perspective view of a filter element containing afiltration media pack according to the present invention.

FIG. 22 is a perspective view of a filter element containing afiltration media pack according to the present invention.

FIG. 23 is a bottom, perspective view of the filter element of FIG. 22.

FIG. 24 is a side view of the sensor board of the filter element ofFIGS. 22 and 23.

FIG. 25 is a partial, sectional view of a filter arrangement containinga filtration media pack according to the present invention.

FIG. 26 is a partial, sectional view of a cleaner having a filterelement containing a filtration media pack according to the presentinvention.

FIG. 27 is a perspective view of an exemplary filter element containinga filtration media pack according to the present invention.

FIG. 28 is a perspective view of an exemplary filter element containinga filtration media pack according to the present invention.

DETAILED DESCRIPTION Fluted Filtration Media

Fluted filtration media can be used to provide fluid filterconstructions in a variety of manners. One well known manner is as az-filter construction. The terms “z-filter construction” or “z-filtermedia” as used herein, is meant to refer to a filter elementconstruction in which individual ones of corrugated, folded, pleated, orotherwise formed filter flutes are used to define longitudinal filterflutes for fluid flow through the media; the fluid flowing along theflutes between inlet and outlet flow ends (or flow faces) of the filterelement. Some examples of z-filter media filter elements are provided inU.S. Pat. Nos. 5,820,646; 5,772,883; 5,902,364; 5,792,247; 5,895,574;6,210,469; 6,190,432; 6,350,296; 6,179,890; 6,235,195; Des. 399,944;Des. 428,128; Des. 396,098; Des. 398,046; and, Des. 437,401; each ofthese fifteen cited references being incorporated herein by reference.

The fluid that can be filtered by the filtration media pack includesgaseous substance and liquid substances. Exemplary gaseous substancesthat can be filtered includes air. Exemplary liquid substances that canbe filtered include water, oil, fuel, and hydraulic fluid. A preferredtype of fluid to be filtered by the filtration media pack includes air.In general, much of the discussion is directed at filtering air. Itshould be understood, however, that the filtration media pack can beused to filter other gaseous substances and other liquid substances.

One type of z-filter media utilizes two media components joined togetherto form the media construction. The two components are: (1) a fluted(for example, corrugated) media sheet; and, (2) a facing media sheet.The facing media sheet is typically non-corrugated, however it can becorrugated, for example perpendicularly to the flute direction asdescribed in International Publication No. WO 2005/077487, publishedAug. 25, 2005, incorporated herein by reference. Alternatively, thefacing sheet can be a fluted (for example, corrugated) media sheet andthe flutes or corrugations may be aligned with or at angles to thefluted media sheet. Although the facing media sheet can be fluted orcorrugated, it can be provided in a form that is not fluted orcorrugated. Such a form can include a flat sheet. When the facing mediasheet is not fluted, it can be referred to as a non-fluted media sheetor as a non-fluted sheet.

The type of z-filter media that utilizes two media components joinedtogether to form the media construction wherein the two components are afluted media sheet and a facing media sheet can be referred to as a“single facer media” or as a “single faced media.” In certain z-filtermedia arrangements, the single facer media (the fluted media sheet andthe facing media sheet), together, can be used to define media havingparallel inlet and outlet flutes. In some instances, the fluted sheetand non-fluted sheet are secured together and are then coiled to form az-filter media construction. Such arrangements are described, forexample, in U.S. Pat. Nos. 6,235,195 and 6,179,890, each of which isincorporated herein by reference. In certain other arrangements, somenon-coiled sections of fluted media secured to flat media, are stackedon one another, to create a filter construction. An example of this isdescribed in FIG. 11 of U.S. Pat. No. 5,820,646, incorporated herein byreference. In general, arrangements where the z-filter media is coiledcan be referred to as coiled arrangements, and arrangements where thez-filter media is stacked can be referred to as stacked arrangements.Filter elements can be provided having coiled arrangements or stackedarrangements.

Typically, coiling of the fluted sheet/facing sheet combination (e.g.,the single facer media) around itself, to create a coiled media pack, isconducted with the facing sheet directed outwardly. Some techniques forcoiling are described in International Publication No. WO 2004/082795,published Sep. 30, 2004, incorporated herein by reference. The resultingcoiled arrangement generally has, as the outer surface of the mediapack, a portion of the facing sheet, as a result. If desired, the singlefacer media can be coiled so that the fluted sheet forms the outersurface of the media pack.

The term “corrugated” used herein to refer to structure in media, ismeant to refer to a flute structure resulting from passing the mediabetween two corrugation rollers, i.e., into a nip or bite between tworollers, each of which has surface features appropriate to cause acorrugation affect in the resulting media. The term “corrugation” is notmeant to refer to flutes that are formed by techniques not involvingpassage of media into a bite between corrugation rollers. However, theterm “corrugated” is meant to apply even if the media is furthermodified or deformed after corrugation, for example by the foldingtechniques described in PCT WO 04/007054, published Jan. 22, 2004,incorporated herein by reference.

Corrugated media is a specific form of fluted media. Fluted media ismedia which has individual flutes (for example, formed by corrugating orfolding or pleating) extending thereacross. Fluted media can be preparedby any technique that provides the desired flute shapes. Whilecorrugating can be a useful technique for forming flutes having aparticular size. When it is desirable to increase the height of theflutes (the height is the elevation between peaks), corrugatingtechniques might not be practical and it may be desirable to fold orpleat the media. In general, pleating of media can be provided as aresult of folding the media. In general, forming flutes by pleating canbe referred to as micropleating. An exemplary technique for folding themedia to provide pleats includes scoring and using pressure to createthe fold.

Filter element or filter cartridge configurations utilizing z-filtermedia are sometimes referred to as “straight through flowconfigurations” or by variants thereof. In general, in this context whatis meant is that the serviceable filter elements generally have an inletflow end (or face) and an exit flow end (or face), with flow enteringand exiting the filter cartridge in generally the same straight throughdirection. The term “straight through flow configuration” disregards,for this definition, air flow that passes out of the media pack throughthe outermost wrap of facing media. In some instances, each of the inletflow end and outlet flow end can be generally flat or planar, with thetwo parallel to one another. However, variations from this, for examplenon-planar faces, are possible in some applications. Furthermore, thecharacterization of an inlet flow face and an opposite exit flow face isnot a requirement that the inlet flow face and the outlet flow face areparallel. The inlet flow face and the exit flow face can, if desired, beprovided as parallel to each other. Alternatively, the inlet flow faceand the outlet flow face can be provided at an angle relative to eachother so that the faces are not parallel. In addition, non-planar facescan be considered non-parallel faces.

A straight through flow configuration is, for example, in contrast tocylindrical pleated filter cartridges of the type shown in U.S. Pat. No.6,039,778, in which the flow generally makes a substantial turn as itspasses through the serviceable cartridge. That is, in a U.S. Pat. No.6,039,778 filter, the flow enters the cylindrical filter cartridgethrough a cylindrical side, and then turns to exit through an end facein a forward-flow system. In a reverse-flow system, the flow enters theserviceable cylindrical cartridge through an end face and then turns toexit through a side of the cylindrical filter cartridge. An example ofsuch a reverse-flow system is shown in U.S. Pat. No. 5,613,992.

The filter element or filter cartridge can be referred to as aserviceable filter element or filter cartridge. The term “serviceable”in this context is meant to refer to a media containing filter cartridgethat is periodically removed and replaced from a corresponding aircleaner. An air cleaner that includes a serviceable filter element orfilter cartridge is constructed to provide for the removal andreplacement of the filter element or filter cartridge. In general, theair cleaner can include a housing and an access cover wherein the accesscover provides for the removal of a spent filter element and theinsertion of a new or cleaned (reconditioned) filter element.

The term “z-filter media construction” and variants thereof as usedherein, without more, is meant to refer to any or all of: a single facermedia containing a fluted media sheet and a facing media sheet withappropriate closure to inhibit air flow from one flow face to anotherwithout filtering passage through the filter media; and/or, a singlefacer media that is coiled or stacked or otherwise constructed or formedinto a three dimensional network of flutes; and/or, a filterconstruction including a single facer media; and/or, a fluted mediaconstructed or formed (e.g., by folding or pleating) into a threedimensional network of flutes. In general, it is desirable to provide anappropriate flute closure arrangement to inhibit unfiltered air thatflows in one side (or face) of the media from flowing out the other side(or face) of the media as part of the filtered air stream leaving themedia. In many arrangements, the z-filter media construction isconfigured for the formation of a network of inlet and outlet flutes,inlet flutes being open at a region adjacent an inlet face and beingclosed at a region adjacent an outlet face; and, outlet flutes beingclosed adjacent an inlet face and being open adjacent an outlet face.However, alternative z-filter media arrangements are possible, see forexample U.S. 2006/0091084 A1, published May 4, 2006 to Baldwin Filters,Inc. also comprising flutes extending between opposite flow faces, witha seal arrangement to prevent flow of unfiltered air through the mediapack. In many z-filter constructions according to the invention,adhesive or sealant can be used to close the flutes and provide anappropriate seal arrangement to inhibit unfiltered air from flowing fromone side of the media to the other side of the media. Plugs, folds ofmedia, or a crushing of the media can be used as techniques to provideclosure of flutes to inhibit the flow of unfiltered air from one side ofthe media (face) to the other side of the media (face).

An alternative z-filter construction can be provided utilizing a flutedmedia sheet. For example, the fluted media sheet can be folded to createclosures at the inlet flow face and the exit flow face. An example ofthis type of arrangement can be seen in, for example, U.S. 2006/0151383to AAF-McQuay Inc. and WO 2006/132717 to Fleetguard, Inc., that describefluted media having folds or bends perpendicular to the flute directionto seal the ends of the flutes.

Referring to FIG. 1, an exemplary type of media 1 useable as z-filtermedia is shown. Although the media 1 is representative of prior artmedia, many of the terms relied upon for describing the media 1 can alsodescribe portions of the media according to the invention. The media 1is formed from a fluted (in the example corrugated) sheet 3 and a facingsheet 4. In general, the fluted corrugated sheet 3 is of a typegenerally characterized herein as having a regular, curved, wave patternof flutes or corrugations 7. The term “wave pattern” in this context, ismeant to refer to a flute or corrugated pattern of alternating troughs 7b and hills 7 a. The term “regular” in this context is meant to refer tothe fact that the pairs of troughs and hills (7 b, 7 a) alternate withgenerally the same repeating corrugation (or flute) shape and size.(Also, typically in a regular configuration each trough 7 b issubstantially an inverse of each hill 7 a.) The term “regular” is thusmeant to indicate that the corrugation (or flute) pattern comprisestroughs and hills with each pair (comprising an adjacent trough andhill) repeating, without substantial modification in size and shape ofthe corrugations along at least 70% of the length of the flutes. Theterm “substantial” in this context, refers to a modification resultingfrom a change in the process or form used to create the corrugated orfluted sheet, as opposed to minor variations from the fact that themedia sheet forming the fluted sheet 3 is flexible. With respect to thecharacterization of a repeating pattern, it is not meant that in anygiven filter construction, an equal number of hills and troughs isnecessarily present. The media 1 could be terminated, for example,between a pair comprising a hill and a trough, or partially along a paircomprising a hill and a trough. (For example, in FIG. 1 the media 2depicted in fragmentary has eight complete hills 7 a and seven completetroughs 7 b.) Also, the opposite flute ends (ends of the troughs andhills) may vary from one another. Such variations in ends aredisregarded in these definitions, unless specifically stated. That is,variations in the ends of flutes are intended to be covered by the abovedefinitions.

In the context of fluted filtration media, and in particular theexemplary media 1, the troughs 7 b and hills 7 a can be characterized aspeaks. That is, the highest point of the hills 7 a can be characterizedas peaks and the lowest points of the troughs 7 b can be characterizedas peaks. The combination of the fluted sheet 3 and the facing sheet 4can be referred to as the single facer media 5. The peaks formed at thetroughs 7 b can be referred to as internal peaks because they facetoward the facing sheet 3 of the single facer media 5. The peaks formedat the hills 7 a can be characterized as external peaks because theyface away from the facing sheet 3 forming the single facer media 5. Forthe single facer media 5, the fluted sheet 3 includes repeating internalpeaks at 7 b that face toward the facing sheet 4, and repeating externalpeaks at 7 a that face away from the facing sheet 4.

The term “regular” when used to characterize a flute pattern is notintended to characterize media that can be considered “tapered.” Ingeneral, a taper refers to a reduction or an increase in the size of theflute along a length of the flute. In general, filtration media that istapered can exhibit a first set of flutes that decrease in size from afirst end of the media to a second end of the media, and a second set offlutes that increase in size from the first end of the media to thesecond end of the media. In general, a tapered pattern is not considereda regular pattern. It should be understood, however, that z-media cancontain regions that are considered regular and regions that areconsidered non-regular along the flute length. For example, a first setof flutes may be considered regular along a distance of the flutelength, such as, one quarter the distance to three quarters thedistance, and then for the remaining amount of the flute length can beconsidered non-regular as a result of the presence of a taper. Anotherpossible flute configuration is to have a tapered-regular-taperedarrangement where, for example, a flute tapers from a first face to apre-selected location, the flute then can be considered regular until asecond pre-determined location, and then the flute tapers to the secondface. Another alternative arrangement can be provided as aregular-taper-regular arrangement, or as a regular-taper arrangement.Various alternative arrangements can be constructed as desired.

In the context of z-media, there are generally two types of “asymmetry.”One type of asymmetry is referred to as area asymmetry, and the othertype of asymmetry is referred to volume asymmetry. In general, areaasymmetry refers to an asymmetry in flute cross-sectional area, and canbe exhibited by tapered flutes. For example, area asymmetry exists if afluted area at one location along the length of a flute is differentfrom the fluted area at another location along the length of the flute.Because tapered flutes exhibit a decrease in size from a first location(e.g., end) to a second location (e.g., end) of the media pack or anincrease in size from a first location (e.g., end) to a second location(e.g., end) of the media pack, there is an area asymmetry. Thisasymmetry (area asymmetry) is a type of asymmetry resulting fromtapering and, as a result, media having this type of asymmetry can bereferred to as non-regular. Another type of asymmetry can be referred toas volumetric asymmetry and will be explained in more detail. Volumetricasymmetry refers to a difference between a dirty side volume and a cleanside volume within the filter media pack. Media exhibiting volumeasymmetry can be characterized as regular if the wave pattern isregular, and the media can be characterized as non-regular if the wavepattern is non-regular.

Z-media can be provided where at least a portion of the flutes areclosed to the passage of unfiltered air by a technique other thanproviding a plug of adhesive or sealant. For example, the ends of flutescan be folded or crushed to provide a closure. One technique forproviding a regular and consistent fold pattern for closing flutes canbe referred to as darting. Darted flutes or darting generally refers tothe closure of a flute wherein the closure occurs by folding the fluteto create a regular fold pattern to collapse the flutes toward thefacing sheet to provide a closure rather than by crushing. Dartinggenerally implies a systematic approach to closing the ends of flutes asa result of folding portions of the flute so that the flute closures aregenerally consistent and controlled. For example, U.S. PatentPublication No. US 2006/0163150 A1 discloses flutes having a dartedconfiguration at the ends of the flutes. The darted configuration canprovide advantages including, for example, a reduction in the amount ofsealant needed to provide a seal, an increased security in theeffectiveness of the seal, and a desirable flow pattern over the dartedend of the flutes. Z-media can include flutes having darted ends, andthe entire disclosure of U.S. Patent Publication No. US 2006/0163150 A1is incorporated herein by reference. It should be understood that theexistence of darts at the ends of flutes does not render the medianon-regular.

In the context of the characterization of a “curved” wave pattern, theterm “curved” is meant to refer to a pattern that is not the result of afolded or creased shape provided to the media, but rather the apex ofeach hill 7 a and the bottom of each trough 7 b is formed along aradiused curve. Although alternatives are possible, a typical radius forsuch z-filter media would be at least 0.25 mm and typically would be notmore than 3 mm. Media that is not curved, by the above definition, canalso be useable. For example, it can be desirable to provide peakshaving a radius that is sufficiently sharp so that it is not considered“curved.” In general, if the radius is less than 0.25 mm, or less than0.20 mm, the ridge or bottom can be characterized as bent, folded, orcreased. In order to reduce masking, it can be desirable to provide apeak with a knife edge. The ability to provide a knife edge at the peakcan be limited by the equipment used to form the media, the mediaitself, and the conditions under which the media is subjected. Forexample, it is desirable to not cut or tear the media. Accordingly,using a knife edge to create the peak can be undesirable if the knifeedge causes a cut or tear in the media. Furthermore, the media can betoo light or too heavy to provide a sufficiently non-curved peak withoutcutting or tearing. Furthermore, the humidity of the air duringprocessing can be enhanced to help create a tighter radius when formingthe peak.

An additional characteristic of the particular regular, curved, wavepattern depicted in FIG. 1, for the corrugated sheet 3, is that atapproximately a midpoint 30 between each trough 7 b and each adjacenthill 7 a, along most of the length of the flutes 7, is located atransition region where the curvature inverts. For example, viewing backside or face 3 a, FIG. 1, trough 7 b is a concave region, and hill 7 ais a convex region. Of course when viewed toward front side or face 3 b,trough 7 b of side 3 a forms a hill; and, hill 7 a of face 3 a, forms atrough. In some instances, region 30 can be a straight segment, insteadof a point, with curvature inverting at ends of the segment 30. When theregion 30 is provided as a straight segment, the wave pattern depictedin FIG. 1, for example, can be characterized as an “arc-straight-arc”wave pattern because of the repeating pattern of curve at the hill 7 a,straight segment at the region 30, and curve at the trough 7 b.

A characteristic of the particular regular, curved, wave patterncorrugated sheet 3 shown in FIG. 1, is that the individual corrugationsare generally straight. By “straight” in this context, it is meant thatthrough at least 50% and preferably at least 70% (typically at least80%) of the length between edges 8 and 9, the hills 7 a and troughs 7 bdo not change substantially in cross-section. The term “straight” inreference to corrugation pattern shown in FIG. 1, in part distinguishesthe pattern from the tapered flutes of corrugated media described inFIG. 1 of WO 97/40918 and PCT Publication WO 03/47722, published Jun.12, 2003, incorporated herein by reference. The tapered flutes of FIG. 1of WO 97/40918, for example, would be a curved wave pattern, but not a“regular” pattern, or a pattern of straight flutes, as the terms areused herein.

Referring to FIG. 1 and as referenced above, the media 2 has first andsecond opposite edges 8 and 9. For the example shown, when the media 2is coiled and formed into a media pack, in general edge 9 will form aninlet end for the media pack and edge 8 an outlet end, although anopposite orientation is possible in some applications.

In the example shown, adjacent edge 8 is provided sealant, in thisinstance in the form of a sealant bead 10, sealing the fluted sheet 3and the facing sheet 4 together. Bead 10 will sometimes be referred toas a “single facer” bead, since it is a bead between the corrugatedsheet 3 and the facing sheet 4, which forms the single facer media 5.Sealant bead 10 seals closed individual flutes 11 adjacent edge 8, topassage of air therefrom.

In the example shown, at adjacent edge 9 is provided sealant, in thisinstance in the form of a sealant bead 14. Sealant bead 14 generallycloses flutes 15 to passage of unfiltered fluid therein, adjacent edge9. Bead 14 would typically be applied as the media 2 is coiled aboutitself, with the corrugated sheet 3 directed to the inside. Thus, bead14 will form a seal between a back side 17 of facing sheet 4, and side18 of the fluted sheet 3. The bead 14 will sometimes be referred to as a“winding bead” since it is typically applied, as the strip 2 is coiledinto a coiled media pack. If the media 2 is cut in strips and stacked,instead of coiled, bead 14 would be a “stacking bead.”

Referring to FIG. 1, once the media 1 is incorporated into a media pack,for example by coiling or stacking, it can be operated as follows.First, air in the direction of arrows 12, would enter open flutes 11adjacent end 9. Due to the closure at end 8, by bead 10, the air wouldpass through the media shown by arrows 13. It could then exit the mediapack, by passage through open ends 15 a of the flutes 15, adjacent end 8of the media pack. Of course operation could be conducted with air flowin the opposite direction.

In more general terms, a z-filter media pack can be characterized ascomprising fluted filter media secured to facing filter media, andconfigured in a media pack of flutes extending between first and secondflow faces. A sealant or seal arrangement is provided within the mediapack, to ensure that air entering flutes at a first upstream flow faceor edge cannot exit the media pack from a downstream flow face or edge,without filtering passage through the media. Alternately stated, az-filter media pack is closed to passage of unfiltered air therethrough,between the inlet flow face and the outlet flow face, typically by asealant arrangement or other arrangement. An additional alternativecharacterization of this is that a first portion of the flutes areclosed or sealed to prevent unfiltered air from flowing into the firstportion of flutes, and a second portion of the flutes are closed orsealed to prevent unfiltered air from flowing out of the second portionof flutes so that air passing into one of the first face or the secondface of the media pack and out the other of the first face or the secondface of the media pack passes through media to provide filtration of theair.

For the particular arrangement shown herein in FIG. 1, the parallelcorrugations 7 a, 7 b are generally straight completely across themedia, from edge 8 to edge 9. Straight flutes or corrugations can bedeformed or folded at selected locations, especially at ends.Modifications at flute ends for closure are generally disregarded in theabove definitions of “regular,” “curved,” and “wave pattern.”

In general, the filter media is a relatively flexible material,typically a non-woven fibrous material (of cellulose fibers, syntheticfibers or both) often including a resin therein, sometimes treated withadditional materials. Thus, it can be conformed or configured into thevarious fluted, for example corrugated, patterns, without unacceptablemedia damage. Also, it can be readily coiled or otherwise configured foruse, again without unacceptable media damage. Of course, it must be of anature such that it will maintain the required fluted (for examplecorrugated) configuration, during use.

In the corrugation or fluting process, an inelastic deformation iscaused to the media. This prevents the media from returning to itsoriginal shape. However, once the tension is released the flutes orcorrugations will tend to spring back, recovering only a portion of thestretch and bending that has occurred. The facing sheet is sometimestacked to the fluted sheet, to inhibit this spring back in the fluted(or corrugated) sheet.

Also, the media can contain a resin. During the corrugation process, themedia can be heated to above the glass transition point of the resin.When the resin cools, it will help to maintain the fluted shapes.

The media of the fluted sheet 3, facing sheet 4 or both, can be providedwith a fine fiber material on one or both sides thereof, for example inaccord with U.S. Pat. Nos. 6,955,775, 6,673,136, and 7,270,693,incorporated herein by reference. In general, fine fiber can be referredto as polymer fine fiber (microfiber and nanofiber) and can be providedon the media to improve filtration performance. As a result of thepresence of fine fiber on the media, it may be possible or desirable toprovide media having a reduced weight or thickness while obtainingdesired filtration properties. Accordingly, the presence of fine fiberon media can provide enhanced filtration properties, provide for the useof thinner media, or both. Fiber characterized as fine fiber can have adiameter of about 0.001 micron to about 10 microns, about 0.005 micronto about 5 microns, or about 0.01 micron to about 0.5 micron. Nanofiberrefers to a fiber having a diameter of less than 200 nanometer or 0.2micron. Microfiber can refer to fiber having a diameter larger than 0.2micron, but not larger than 10 microns. Exemplary materials that can beused to form the fine fibers include polyvinylidene chloride, polyvinylalcohol polymers and co-polymers comprising various nylons such as nylon6, nylon 4,6, nylon 6,6, nylon 6,10, and co-polymers thereof, polyvinylchloride, PVDC, polystyrene, polyacrylonitrile, PMMA, PVDF, polyamides,and mixtures thereof.

Still referring to FIG. 1, at 20 tack beads are shown positioned betweenthe fluted sheet 3 and facing sheet 4, securing the two together. Thetack beads 20 can be for example, discontinuous lines of adhesive. Thetack beads can also be points in which the media sheets are weldedtogether.

From the above, it will be apparent that the exemplary fluted sheet 3depicted is typically not secured continuously to the facing sheet,along the troughs or hills where the two adjoin. Thus, air can flowbetween adjacent inlet flutes, and alternately between the adjacentoutlet flutes, without passage through the media. However, unfilteredair which has entered a flute through the inlet flow face cannot exitfrom a flute through the outlet flow face without passing through atleast one sheet of media, with filtering.

Attention is now directed to FIG. 2, in which a z-filter mediaconstruction 40 utilizing a fluted (in this instance regular, curved,wave pattern) sheet 43, and a non-corrugated flat, facing sheet 44, isdepicted. The distance D1, between points 50 and 51, defines theextension of flat media 44 in region 52 underneath a given flute 53. Thepoints 50 and 51 are provided as the center point of the internal peaks46 and 48 of the fluted sheet 43. In addition, the point 45 can becharacterized as the center point of the external peak 49 of the flutedsheet 43. The distance D1 defines the period length or interval of themedia construction 40. The length D2 defines the arcuate media lengthfor the flute 53, over the same distance D1, and is of course largerthan D1 due to the shape of the flute 53. For a typical regular shapedmedia used in fluted filter applications according to the prior art, theratio of the lengths D2 to D1 is typically within a range of 1.2-2.0,inclusive. An exemplary arrangement common for air filters has aconfiguration in which D2 is about 1.25×D1 to about 1.35×D1. Such mediahas, for example, been used commercially in Donaldson Powercore™Z-filter arrangements having a regular, curved, wave pattern. Herein theratio D2/D1 will sometimes be characterized as the flute/flat ratio orthe media draw for the media.

The flute height J is the distance from the facing sheet 44 to thehighest point of the fluted sheet 43. Alternatively stated, the fluteheight J is the difference in exterior elevation between alternatingpeaks 57 and 58 of the fluted sheet 43. The flute height J takes intoaccount the thickness of the fluted sheet 43. The peak 57 can bereferred to as the internal peak (the peak directed toward the facingsheet 44), and the peak 58 can be referred to as the external peak (thepeak directed away from the facing sheet 44). Although the distances D1,D2, and J are applied to the specific fluted media arrangement shown inFIG. 2, these distances can be applied to other configurations of flutedmedia where D1 refers to the period length of a flute or the distance offlat media underneath a given flute, D2 refers to the length of flutedmedia from lower peak to lower peak, and J refers to the flute height.

Another measurement can be referred to as the cord length (CL). The cordlength refers to the straight line distance from the center point 50 ofthe lower peak 57 and the center point 45 of the upper peak 58. Thethickness of the media and the decision where to begin or end aparticular distance measurement can affect the distance value becausethe media thickness affects the distance value. For example, the cordlength (CL) can have different values depending upon whether thedistance is measured from the bottom of the internal peak to the bottomof the external peak or whether it is measured from the bottom of theinternal peak to the top of the external peak. This difference indistance is an example of how the media thickness effects the distancemeasurement. In order to minimize the effect of the thickness of themedia, the measurement for cord length is determined from a center pointwithin the media. The relationship between the cord length CL and themedia length D2 can be characterized as a media-cord percentage. Themedia-cord percentage can be determined according to the followingformula:

$\text{media-cord~~percentage} = \frac{\left( {{1\text{/}2D\; 2} - {CL}} \right) \times 100}{CL}$

In the corrugated cardboard industry, various standard flutes have beendefined. These include, for example, the standard E flute, standard Xflute, standard B flute, standard C flute, and standard A flute. FIGS.3A-3G, attached, in combination with Table 1 below provides definitionsof these flutes.

Donaldson Company, Inc., (DCI) the assignee of the present disclosure,has used variations of the standard A and standard B flutes, in avariety of z-filter arrangements. The DCI standard B flute can have amedia-cord percentage of about 3.6%. The DCI standard A flute can have amedia-cord percentage of about 6.3. Various flutes are also defined inTable 1 and FIGS. 3A-G. FIG. 2 shows a z-filter media construction 40utilizing the standard B flute as the fluted sheet 43.

TABLE 1 (Flute definitions for FIGS. 3A-3G) DCI A Flute: Flute/flat =1.52:1; The Radii (R) are as follows: R1000 = .0675 inch (1.715 mm):R1001 = .0581 inch (1.476 mm); R1002 = .0575 inch (1.461 mm); R1003 =.0681 inch (1.730 mm); DCI B Flute: Flute/flat = 1.32:1; The Radii (R)are as follows: R1004 = .0600 inch (1.524 mm): R1005 = .0520 inch (1.321mm); R1006 = .0500 inch (1.270 mm); R1007 = .0620 inch (1.575 mm); Std.E Flute: Flute/flat = 1.24:1; The Radii (R) are as follows: R1008 =.0200 inch (.508 mm); R1009 = .0300 inch (.762 mm); R1010 = .0100 inch(.254 mm); R1011 = .0400 inch (1.016 mm); Std. X Flute: Flute/flat =1.29:1; The Radii (R) are as follows: R1012 = .0250 inch (.635 mm);R1013 = .0150 inch (.381 mm); Std. B Flute: Flute/flat =1.29:1; TheRadii (R) are as follows: R1014 = .0410 inch (1.041 mm); R1015 = .0310inch (.7874 mm); R1016 = .0310 inch (.7874 mm); Std. C Flute: Flute/flat= 1.46:1; The Radii (R) are as follows: R1017 = .0720 inch (1.829 mm);R1018 = .0620 inch (1.575 mm); Std. A Flute: Flute/flat = 1.53:1; TheRadii (R) are as follows: R1019 = .0720 inch (1.829 mm); R1020 = .0620inch (1.575 mm).

In general, standard flute configurations from the corrugated boxindustry have been used to define corrugation shapes or approximatecorrugation shapes for corrugated media. Improved performance offiltration media can be achieved by providing a flute configuration orstructure that enhances filtration. In the corrugated box boardindustry, the size of the flutes or the geometry of the corrugation wasselected to provide a structure suited for handling a load. The flutegeometry in the corrugated box industry developed the standard A fluteor B flute configuration. While such flute configurations can bedesirable for handling a load, filtration performance can be enhanced byaltering the flute geometry. Techniques for improving filtrationperformance include selecting geometries and configurations that improvefiltration performance in general, and that improve filtrationperformance under selected filtration conditions. Exemplary flutegeometries and configurations that can be altered to improve filtrationperformance include flute masking, flute shape, flute width heightratio, and flute asymmetry. In view of the wide selection of flutegeometries and configurations, the filter element can be configured withdesired filter element geometries and configurations in view of thevarious flute geometries and configurations to improve filtrationperformance.

Masking

In the context of z-media, masking refers to the area of proximitybetween the fluted sheet and the facing sheet where there is a lack ofsubstantial pressure difference resulting in a lack of useful filtrationmedia when the filtration media is in use. In general, masked media isnot useful for significantly enhancing the filtration performance offiltration media. Accordingly, it is desirable to reduce masking tothereby increase the amount of filtration media available for filtrationand thereby increase the capacity of the filtration media, increase thethroughput of the filtration media, decrease the pressure drop of thefiltration media, or some or all of these.

In the case of a fluted sheet arranged in a pattern with broad radii atthe peaks as shown in FIG. 2, there exists a relatively large area offiltration media proximate the contact area of the fluted sheet and thefacing sheets that is generally not available for filtration. Maskingcan be reduced by decreasing the radii of the peak or contact pointbetween the fluted sheet and the facing sheet (e.g., providing sharpercontact points). Masking generally takes into account the deflection ofthe media when it is under pressure (e.g., during filtration). Arelatively large radius may result in more of the fluted media beingdeflected toward the facing sheet and thereby increasing masking. Byproviding a sharper peak or contact point (e.g., a smaller radius),masking can be reduced.

Attempts have been made to reduce the radii of contact between thefluted sheet and the facing sheet. For example, see U.S. Pat. No.6,953,124 to Winter et al. An example of reducing the radii is shown inFIG. 4A where the fluted sheet 70 contacts the facing sheets 72 and 73at relatively sharp peaks or contact points 74 and 75 in the flutedsheet 70. A curved wave pattern such as the curved wave pattern shown inFIG. 1 generally provides a fluted sheet having a radius at the peaks ofat least 0.25 mm and typically not more than 3 mm. A relatively sharppeak or contact point can be characterized as a peak having a radius ofless than 0.25 mm. Preferably, the relatively sharp peak or contact peakpoint can be provided having a radius of less than about 0.20 mm. Inaddition, masking can be reduced by providing a peak having a radius ofless than about 0.15 mm, and preferably less than about 0.10 mm. Thepeak can be provided having no radius or essentially a radius of about 0mm. Exemplary techniques for providing fluted media exhibitingrelatively sharp peaks or contact points includes coining, bending,folding, or creasing the fluted media in a manner sufficient to providea relatively sharp edge. It should be understood that the ability toprovide a sharp edge depends on a number of factors including thecomposition of the media itself and the processing equipment used forproviding coining, bending, folding, or creasing. In general, theability to provide a relatively sharp contact point depends on theweight of the media and whether the media contains fibers that resisttearing or cutting. In general, it is desirable to not cut thefiltration media during coining, bending, folding, or creasing. While itis desirable to reduce the radius of the peak (internal peak or externalpeak) to reduce masking, it is not necessary that all of the peaks havea reduced radius to decrease masking. Reduced masking, and enhancedfiltration performance, can be achieved by providing at least some ofthe peaks (e.g., at least about 20% of the peaks) with a relativelysharp peak or contact point. Furthermore, depending on the design of themedia, the external peaks can be provided with a reduced radius or theinternal peaks can be provided with a reduced radius, or both theexternal peaks and the internal peaks can be provided with a reducedradius in order to decrease masking.

Increasing the Surface Area of Media

Filtration performance can be enhanced by increasing the amount offiltration media available for filtration. Reducing masking can beconsidered a technique for increasing the surface area of mediaavailable for filtration.

Now referring to FIG. 4A, the fluted sheet 70 can be considered toprovide flutes having a cross-section resembling an equilateraltriangle. Because the media is flexible, it is expected that when themedia is subjected to pressure such as during filtration, the flutedsheet 70 may deflect. In addition, the fluted sheet 43 in FIG. 2 can beconsidered to have flutes resembling a triangular shape. In general,fluted media where the flutes resemble equilateral triangles generallyprovides the least amount of media available for filtration comparedwith other flute designs where the period length or interval D1 isincreased or decreased, or the flute height J is increased or decreased,relative to the other.

Now referring to FIGS. 4B and 4C, FIG. 4B refers to media where thefluted sheet 80 extends between the facing sheets 82 and 83. FIG. 4Cshows media where the fluted sheet 90 extends between the facing sheets92 and 93. The fluted sheet 80 is shown having a longer flute period D1than the fluted sheet 70 in FIG. 4A. The fluted sheet 80 is providedhaving a relatively long period D1 relative to the flute height Jcompared with the media configuration shown in FIG. 4A. Now referring toFIG. 4C, the fluted sheet 90 is shown having a shorter flute period D1than the fluted sheet 70 in FIG. 4A. The fluted sheet 90 is shown havinga relatively large flute height J relative to the period D1 comparedwith the media configuration shown in FIG. 4A.

The configuration of the fluted media can be characterized by the flutewidth height ratio. The flute width height ratio is the ratio of theflute period length D1 to the flute height J. The flute width heightratio can be expressed by the following formula:

$\text{flute~~width~~height~~ratio} = \frac{D\; 1}{J}$

Measured distances such as flute period length D1 and the flute height Jcan be characterized as average values for the filtration media alongthe flute length excluding 20% of the flute length at each end. Thedistances can be measured away from the ends of the flutes. It istypically the ends of the flutes that have a sealant or closure. Theflute width height ratio calculated at a flute closure would notnecessarily represent the flute width height ratio of the flute wherethe filtration is taking place. Accordingly, the measure of flute widthheight ratio can be provided as an average value over the flute lengthwith the exception of the last 20% of the flute length near the ends ofthe flutes to remove the effects of flute closure when the flutes areclosed at or near the ends. For “regular” media, it is expected that theflute period length D and the flute height J will be relatively constantalong the flute length. By relatively constant, it is meant that theflute width height ratio can vary within about 10% over the length ofthe flute excluding the 20% length at each end where flute closuredesigns may affect the width height ratio. In addition, in the case of a“non-regular” media, such as, media having tapered flutes, the flutewidth height ratio can vary or remain about the same over the length ofthe flute. By adjusting the flute shape away from a theoreticalequilateral triangle shape, the amount of media in a given volumeavailable for filtration can be increased. Accordingly, flutes having aflute width height ratio of at least about 2.2, at least about 2.5, atleast about 2.7, or at least about 3.0 can provide an increased surfacearea of media available for filtration. In addition, providing a flutedesign having a width height ratio of less than about 0.45, less thanabout 0.40, less than about 0.37, or less than about 0.33 can provideincreased media area available for filtration. In general, a theoreticalflute having an equilateral triangle shape represents a flute widthheight ratio of about 1.6.

Another technique for increasing the amount of filtration mediaavailable for filtration includes increasing the flute density of themedia pack. The flute density refers to the number of flutes percross-sectional area of filtration media in a filtration media pack. Theflute density depends on a number of factors including the flute heightJ, the flute period D1, and the media thickness T. The flute density canbe characterized as a media pack flute density or as a single facermedia flute density. The equation for calculating the media pack flutedensity (p) for a filter element is:

$\rho = \frac{\text{number~~of~~channels~~(open~~and~~closed)}}{2 \times z\text{-media~~pack~~cross sectional~~area}}$

The flute density of a filter element can be calculated by counting thenumber of channels including those channels that are open and thosechannels that are closed in a cross sectional area of the filterelement, and dividing that by two times the cross sectional area of thefilter element at the location where the number of channels wasdetermined. In general, it is expected that the flute density willremain relatively constant across the length of the filter element fromthe inlet flow face to the outlet flow face, or vice versa. It should beunderstood that the z-media cross sectional are refers to the crosssectional area of the media (wound or stacked) and not necessarily tothe cross sectional area of the filter element. The filter element mayhave a sheath or a seal intended to engage a housing that would providethe filter element with a cross-sectional area that is greater than thecross-sectional area of the media. Furthermore, the cross-sectional areaof the media refers to the effective area. That is, if the media iswound around a core or mandrel, the cross-sectional area of the core ormandrel is not part of the z-media pack cross-sectional area.Furthermore, the number of channels refers to the number of channels inthe effective area.

An alternative equation for the calculation of flute density (p) for asingle facer media is:

$\rho = \frac{1}{\left( {J + T} \right) \times D\; 1}$

In the equation for flute density per single facer media, J is the fluteheight, D1 is the flute period length, and T is the thickness of thefluted sheet. This alternate equation can be referred to as the equationfor calculating the single facer media flute density. The single facermedia flute density is determined based upon the configuration of thesingle facer media. In contrast, the media pack flute density isdetermined based upon the assembled media pack

Theoretically, the media pack flute density and the single facer mediaflute density should provide similar results. However, it is possiblethat the media pack may be configured in such a way that the media packflute density and the single facer media flute density provide differentresults.

The standard B flute shown in FIGS. 2 and 3A-G and characterized inTable 1 provides a coiled filtration media having a flute density (mediapack flute density and single facer media flute density) of about 34flute/inch². The media pack formed from standard B flute media can becharacterized as having an average flute density of about 34flute/inch². The flute density (whether expressed as the media packflute density or the single facer media flute density) can be consideredan average flute density for the media pack unless stated otherwise. Theflute density, therefore, may be referred to at times as the flutedensity and at other times as the average flute density. In general,increasing the average flute density refers to providing a media packhaving a flute density greater than the flute density for standard Bflute media. For example, increased flute density can refer to a mediapack having a flute density greater than 35.0 flute/inch². The mediapack can be provided having a flute density of greater than about 36flute/inch², greater than about 38 flute/inch², greater than about 40flute/inch², greater than 45 flute/inch², or greater than about 50flute/inch². The media pack can be provided having a decreased flutedensity (compared with standard B media) to provide decreased pressuredrop or less resistance to flow therethrough. For example, the mediapack can be provided having a media pack flute density of less than 34.0flute/inch², less than about 30 flute/inch², or less than about 25flute/inch².

In general, providing media having increased flute density has atendency to increase the surface area of media within a volume of themedia and, therefore, has a tendency to increase the loading capacity ofthe filtration media. Accordingly, increasing the flute density of mediacan have the effect of enhancing the loading capacity of the media.However, increasing the flute density of media can have the effect ofincreasing the pressure drop through the media assuming other factorsremain constant. Furthermore, decreasing the flute density forfiltration media can have the effect of decreasing initial pressuredrop.

Increasing the flute density of filtration media has the effect ofdecreasing the flute height (J) or the flute period length (D1), orboth. As a result, the size of the flute (the size of the flute refersto cross sectional area of the flute) tends to decrease as flute densityincreases. As a result, smaller flute sizes have the effect ofincreasing the pressure drop across the filtration media. In general,the reference to a pressure drop across the media refers to the pressuredifferential determined at a first face of the media relative to thepressure measured at second face of the media, wherein the first faceand the second face are provided at generally opposite ends of a flute.In order to provide a filtration media having a relatively high flutedensity while retaining a desired pressure drop, the flute length can bedecreased. The flute length refers to the distance from the first faceof the filtration media to the second face of the filtration media. Inthe case of filtration media useful for filtering air for combustionengines, short length flutes can be characterized as those flutes havinga flute length of less than about 5 inches (e.g., about 1 inch to about5 inches, or about 2 inches to about 4 inches). Medium length flutes canbe characterized as those flutes having a length of about 5 inches toabout 8 inches. Long length flutes can be characterized as those fluteshaving a flute length of greater than about 8 inches (e.g., about 8inches to about 12 inches).

Flute Shape

Another technique for increasing the amount of filtration mediaavailable for filtration within a media pack includes selecting a fluteshape that provides for an increased amount of filtration mediaavailable for filtration compared with standard flute designs such asthose described in Table 1. One technique for providing a flute shapethat increases the amount of filtration media available for a filtrationis by creating a ridge between adjacent peaks. As discussed previously,adjacent peaks can be characterized as an internal peak and an externalpeak depending upon whether the peak is facing toward the facing sheetor away from the facing sheet. FIGS. 5A-C show representative exemplaryflute shapes for enhancing filtration performance. The flute shape shownin FIG. 5A can be referred to as a “low contact” flute shape. The fluteshapes shown in FIGS. 5B and 5C can be referred to as a “zero strain”flute shapes. In general, the “low contact” name refers to the abilityof the flute shape to enhance the amount of fluted media sheet betweenthe facing media sheets while reducing the amount of contact (e.g.,masking) between the fluted sheet and the facing sheet compared withstandard A and B fluted media. The “zero strain” name refers to theability of the flute shape to provide a taper along a length of theflutes without inducing an undesired level of strain on the media. Ingeneral, an undesired level of strain (or elongation) in the media canrefer to an amount of strain that causes a tear or rip in the media, oran amount of strain that requires the use of a special media that canwithstand a higher level of strain. In general, media that can withstanda strain of greater than about 12% can be considered a special mediathat an withstand a higher level of strain, and can be more expensivethan media that is equipped to handle strain up to about 12%. The zerostrain fluted sheet can additionally provide for reduced contact (e.g.,reduced masking) between the fluted sheet and the facing sheet.

Now referring to FIGS. 5A-C, the media 110 includes fluted sheet 112between facing sheets 111 and 113, the media 120 includes fluted sheet122 between facing sheets 121 and 123, and the media 140 includes flutedsheet 142 between facing sheets 141 and 143. The combination of thefluted sheet 112 and the facing sheet 113 can be referred to as a singlefacer media 117, the combination of the fluted sheet 122 and the facingsheet 123 can be referred to as the single facer media 137, and thecombination of fluted sheet 142 and facing sheet 143 can be referred toas the single facer media 147. When the single facer media 117, 137, or147 is coiled or stacked, the facing sheet 111, 121, or 141 can beprovided from another single facer media in the case of stacked media orfrom the same single facer media in the case of coiled media.

The media 110, 120, and 140 can be arranged to provide filter elementsfor cleaning a fluid such as air. The filter elements can be arranged ascoiled elements or stacked elements. Coiled elements generally include afluted media sheet and a facing media sheet that is wound to provide thecoiled construction. The coil construction can be provided having ashape that is characterized as round, obround, or racetrack. A stackedconstruction generally includes alternating layers of media comprisingfluted media sheet adhered to facing media sheet. The media 110, 120,and 140 shown in FIGS. 5A-C are sectional views taken across the mediato show the cross-sectional shape of the fluted sheet for the lowcontact and zero strain shapes. It should be understood that thecross-sectional shape can be provided extending along a length of theflute. Furthermore, the flutes can be sealed so that the media functionsas z-media. The seal can be provided, if desired, as an adhesive orsealant material.

In FIG. 5A, the distance D1 is measured from the center point of theinternal peak 114 to the center point of the external peak 116. Thefluted media 110 is shown having two ridges 118 for each period lengthD1, or along the media length D2. The ridges 118 are provided extendingalong at least a portion of the length of the flute. In general, eachridge 118 can be characterized as a general area where a relativelyflatter portion of the fluted media 118 a joins a relatively steeperportion of the fluted media 118 b. A ridge (e.g., a non-peak ridge) canbe considered a line of intersection between differently sloped mediaportions. A ridge can be formed as a result of deformation of the mediaat that location. The media can be deformed at the ridge as a result ofapplying pressure to the media. Techniques for forming the ridge includecoining, creasing, bending, and folding. Preferably, the ridge can beprovided as a result of coining during a corrugation process where thecorrugation rolls apply pressure to the media to form the ridge. Anexemplary technique for forming the fluted sheet and the single spacermedia is described in U.S. Application Ser. No. 61/025,999 that wasfiled with the United States Patent and Trademark Office on Feb. 4,2008. The entire disclosure of U.S. Application Ser. No. 61/025,999 isincorporated herein by reference. It is recognized that a peak can bereferred to as a ridge. In the context of this disclosure, however, thereference to a “ridge” can be seen from context to refer to a “non-peakridge” when the ridge is clearly provided between peaks.

For the exemplary fluted sheet 112, the relatively flatter portion ofthe fluted media 118 a can be seen in FIG. 5A as the portion of thefluted media extending between the external peak 115 and the ridge 118.The average angle of the relatively flatter portion of the fluted media118 a from the external peak 115 to the ridge 118 can be characterizedas less than 45°, and can be provided as less than about 30° relative tothe facing sheet 113. The relatively steeper portion of the fluted media118 b can be characterized as that portion of the media extending fromthe internal peak 116 to the ridge 118. In general, the angle of therelatively steeper portion of the fluted media 118 b, as characterizedas extending between the internal peak 116 and the ridge 118, can begreater than 45° and can be greater than about 60° relative to thefacing sheet 113. It is the difference in angle between the relativelyflatter portion of the fluted media 118 a and the relatively steeperportion of the fluted media 118 b that can characterize the presence ofthe ridge 118. It should be understood that the angle of the relativelyflatter portion of the fluted media 118 a and angle of the relativelysteeper portion of the fluted media 118 b can be determined as theaverage angle between the points that form the end points of the sectionof the media, and the angle is measured from the facing sheet.

The ridge 118 can be provided as a result of coining, creasing, bending,or folding along a length of the fluted sheet 112 during the formationof the fluted media 12. It may be desirable, but it is not necessary,during the step of forming the fluted media 112 to take the steps to setthe ridge 118. For example, the ridge 118 can be set by heat treatmentor moisture treatment or a combination thereof. In addition, the ridge118 can exist as a result of coining, creasing, bending, or folding toform the ridge without an additional step of setting the ridge.Furthermore, the characterization of a ridge 118 is not to be confusedwith the fluted sheet external peaks 115 or 119 and the fluted sheetinternal peaks 116 or 114. The characterization of a generally flatterportion 118 a and a generally steeper portion 118 b is intended as a wayto characterize the presence of a ridge. In general, it is expected thatthe flatter portion 118 a and the steeper portion 118 b will exhibit acurve. That is, it is expected that the flatter portion 18 a and thesteeper portion 118 b will not be completely planar, particularly asfluids such as air flows through the media during filtration.Nevertheless, the angle of the media can be measured from the ridge tothe corresponding, adjacent peak to provide the average angle of thatportion of the media.

The shape of the media depicted in FIG. 5A can be referred to as a lowcontact shape. In general, the low contact shape refers to therelatively low area of contact between the fluted sheet 112 and thefacing sheet 111. The presence of the ridge 118 helps provide forreduced masking at the peaks 115 and 119. The ridge 118 exists as aresult of deforming the fluted sheet 112 and, as a result, reduces theinternal stress on the media at the peaks 115 and 119. Without thepresence of the ridge 118, there would likely exist a level of internaltension in the fluted sheet 112 that would cause the fluted sheet 112 tocreate a greater radius at the peaks 115 and 119, and thereby increasemasking. As a result, the presence of the ridge 118 helps increase theamount of media present between adjacent peaks (e.g., peaks 115 and 114)and helps decrease the radius of a peak (e.g., peak 115) as a result ofrelieving, to a certain extent, the tension within the fluted sheet 112that would cause it to expand or flatten out at the peaks in the absenceof the ridge.

The presence of a ridge 118 can be detected by visual observation. FIG.6 shows a photograph of an end view of a filter element wherein thefluted media can be characterized as having the low contact shape. Whilethe presence of the low contact shape may not be particularly apparentfrom viewing the end of the fluted media, one can cut into the filterelement and see the presence of a ridge extending along a length of aflute. Furthermore, the presence of a ridge can be confirmed by atechnique demonstrated by the photograph of FIG. 7 where the filterelement is loaded with dust, and the fluted sheet can be peeled awayfrom the facing sheet to reveal a cake of dust having a ridgecorresponding to the ridge on the fluted media. In general, the ridge ona cake of dust reflects a portion of the dust surface having an averageangle intersecting another portion of the dust surface having adifferent average angle. The intersection of the two portions of thedust surface cake forms a ridge. The dust that can be used to load themedia to fill the flutes to provide a cake of dust within the flutes canbe characterized as ISO Fine test dust.

Now referring to FIG. 5A, the fluted sheet 112 includes two ridges 118over the distance D2 where the distance D2 refers to the length of thefluted sheet 112 from the center point of the peak 114 to the centerpoint of the peak 116, and wherein the ridges are not the peaks 114,115, 116 or 119. Although the peaks 114 and 116 can be referred to asinternal peaks, and the peaks 115 and 119 can be referred to as theexternal peaks, the peaks can additionally be characterized as thefacing sheet peaks. In general, it is believed that the media will bearranged in different configurations such as wound or stacked and thatthe flutes will be arranged spacially so that the characterizations ofinternal and external can be disregarded in favor of the use of thecharacterization of the peak as a facing sheet peak. The use of theterms internal and external is convenient for describing the flute as itis shown in the figures, and as provided as part of a single facermedia.

Although the fluted sheet 112 can be provided having two ridges 118along each length D2, the fluted sheet 112 can be provided having asingle ridge along each period length D2, if desired, and can beprovided having a configuration where some of the periods exhibit atleast one ridge, some periods exhibit two ridges, and some periodsexhibit no ridge, or any combination thereof. The fluted sheet can beprovided as having a repeating pattern of ridges. A repeating pattern ofridges means that the wave pattern exhibits a pattern of ridges. Thepattern of ridges may be between every adjacent peak, every otheradjacent peak, every third adjacent peak, or some variation that can beperceived over the wave pattern of the media as exhibiting a repeatingpattern of ridges.

The characterization of the presence of a ridge should be understood tomean that the ridge is present along a length of the flute. In general,the ridge can be provided along the flute for a length sufficient toprovide the resulting media with the desired performance. While theridge may extend the entire length of the flute, it is possible that theridge will not extend the entire length of the flute as a result of, forexample, influences at the ends of the flute. Exemplary influencesinclude flute closure (e.g., darting) and the presence of plugs at theends of flutes. Preferably, the ridge extends at least 20% of the flutelength. By way of example, the ridge can extend at least 30% of theflute length, at least 40% of the flute length, at least 50% of theflute length, at least 60% of the flute length, or at least 80% of theflute length. The ends of the flutes may be closed in some manner andthat as a result of the closure, one may or may not be able to detectthe presence of a ridge when viewing the media pack from a face.Accordingly, the characterization of the presence of a ridge asextending along a length of the flute does not mean that the ridge mustextend along the entire length of the flute. Furthermore, the ridge maynot be detected at the ends of the flute. Attention is directed to thephotograph of FIG. 6 where it may be somewhat difficult to detect thepresence of a ridge at the end of fluted media although the presence ofthe ridge can be detected within the media at a distance from the end ofthe flute.

Now referring to FIG. 5B, the fluted media 120 includes a fluted sheet122 provided between facing sheets 121 and 123. The fluted sheet 122includes at least two ridges 128 and 129 between the internal peak 124and the external peak 125. Along the length D2, the media 122 includesfour ridges 128 and 129. A single period length of media can includefour ridges. It should be understood that the ridges 128 and 129 are notthe peaks 124, 125, or 126 that can be referred to as the facing mediapeaks. The media 122 can be provided so that between adjacent peaks(e.g., peaks 125 and 126) there are two ridges 128 and 129. In addition,the media 122 can be provided so that between adjacent peaks, there isone ridge or no ridge. There is no requirement that between eachadjacent peak there are two ridges. There can be an absence of ridgesbetween peaks if it is desirable to have the presence of ridgesalternate or be provided at predetermined intervals between adjacentpeaks.

The ridge 128 can be characterized as the area where a relativelyflatter portion of the fluted media 128 a joins a relatively steeperportion of the fluted media 128 b. In general, the relatively flatterportion of the fluted media 128 a can be characterized as having anangle of less than 45° and preferably less than about 30° wherein theangle is measured between the ridge 128 and the ridge 129, and relativeto the facing sheet 123. The relatively steeper portion of the flutedmedia 128 b can be characterized as having an angle of greater than 45°and preferably greater than about 60° wherein the angle is measured fromthe peak 126 to the ridge 128, and relative to the facing sheet 123. Theridge 129 can be provided as a result of the intersection of therelatively flatter portion of the fluted media 129 a and the relativelysteeper portion of the fluted media 129 b. In general, the relativelyflatter portion of the fluted media 129 a corresponds to the angle ofthe portion of the media extending from the ridge 128 to the ridge 129.In general, the relatively flatter portion of the fluted media 129 a canbe characterized as having a slope of less than 45°, and preferably lessthan about 30°. The relatively steeper portion of the fluted media 129 bcan be characterized as that portion of the fluted media extendingbetween the ridge 129 and the peak 125 and can be characterized ashaving an angle between the ridge 129 and the peak 125 and relative tothe facing sheet 123. In general, the relatively steeper portion of thefluted media 129 b can be characterized as having an angle of greaterthan 45° and preferably greater than about 60°.

Now referring to FIG. 5C, the fluted media 140 includes a fluted sheet142 provided between facing sheets 141 and 143. The fluted sheet 142includes at least two ridges 148 and 149 between the internal peak 144and the external peak 145. Along the length D2, the media 140 includesfour ridges 148 and 149. A single period length of media can includefour ridges. It should be understood that the ridges 148 and 149 are notthe peaks 144 and 145. The media 140 can be provided so that betweenadjacent peaks (e.g., peaks 144 and 145) there are two ridges 148 and149. In addition, the fluted sheet 140 can be provided so that betweenother adjacent peaks, there is one ridge, two ridges, or no ridge. Thereis no requirement that between each adjacent peak there are two ridges.There can be an absence of ridges between peaks if it is desirable tohave the presence of ridges alternate or provided at predeterminedintervals between adjacent peaks. In general, a pattern of flutes can beprovided where the pattern of flutes repeats and includes the presenceof ridges between adjacent peaks.

The ridges 148 and 149 can be characterized as the areas where arelatively flatter portion of the fluted sheet joins a relativelysteeper portion of the fluted sheet. In the case of the ridge 148, arelatively flatter portion of the fluted sheet 148 a joins a relativelysteeper portion of the fluted sheet 148 b. In the case of the ridge 149,a relatively flatter portion of the fluted sheet 149 a joins arelatively steeper portion of the fluted sheet 149 b. The relativelysteeper portion of the fluted media can be characterized as having anangle of greater than 45° and preferably greater than about 60° whenmeasured for that portion of the media relative to the facing sheet 143.The relatively flatter portion can be characterized as having a slope ofless than 45° and preferably less than about 30° for that portion of themedia relative to the facing sheet 143.

The fluted sheet 142 can be considered more advantageous to preparerelative to the fluted sheet 122 because the wrap angle of the flutedsheet 142 can be less than the wrap angle for the fluted sheet 122. Ingeneral, the wrap angle refers to the sum of angles resulting in mediaturns during the step of fluting. In the case of the fluted media 142,the media is turned less during fluting compared with the fluted media122. As a result, by fluting to form the fluted sheet 142, the requiredtencile strength of the media is lower compared with the fluted sheet122.

The fluted sheets 112, 122, and 142 are shown as relatively symmetricalfrom peak to peak. That is, for the fluted sheets 112, 122, and 142, theflutes repeat having the same number of ridges between adjacent peaks.Adjacent peaks refer to the peaks next to each other along a length offluted media. For example, for the fluted media 112, peaks 114 and 115are considered adjacent peaks. A period of media, however, need not havethe same number of ridges between adjacent peaks, and the media can becharacterized as asymmetrical in this manner. That is, the media can beprepared having a ridge on one half of the period and not having a ridgeon the other half of the period.

By providing a single ridge or multiple ridges between adjacent peaks ofthe fluted media, the distance D2 can be increased relative to prior artmedia such as standard A and B flutes. As a result of the presence of aridge or a plurality of ridges, it is possible to provide filtrationmedia having more media available for filtration compared with, forexample, standard A flutes and B flutes. The previously describedmeasurement of media-cord percentage can be used to characterize theamount of media provided between adjacent peaks. The length D2 isdefined as the length of the fluted sheets 112, 122, and 142 for aperiod of the fluted sheets 112, 122, and 142. In the case of the flutedsheet 112, the distance D2 is the length of the fluted sheet from thelower peak 114 to the lower peak 116. This distance includes two ridges118. In the case of the fluted sheet 122, the length D2 is the distanceof the fluted sheet 122 from the lower peak 124 to the lower peak 126.This distance includes at least four ridges 128 and 129. The existenceof increased filtration media between adjacent peaks as a result ofproviding one or more ridge (or crease) between the adjacent peaks canbe characterized by the media-cord percentage. As discussed previously,standard B flutes and standard A flutes typically exhibit a media-cordpercentage of about 3.6% and about 6.3%, respectively. In general, lowcontact flutes such as the flute design shown in FIG. 5A can exhibit amedia-cord percentage of about 6.2% to about 8.2%. Preferably, theflutes exhibit a media-cord percentage greater than 5.2% and preferablygreater than 6.5%. The flute designs shown in FIGS. 5B and 5C canprovide a media-cord percentage of about 7.0% to about 16%. If desired,the media pack can be provided having flutes exhibiting a media-cordpercentage greater than about 6.3%, or greater than about 8.3%.

The filtration media 120 and 140 in FIGS. 5B and 5C have an additionaladvantage of providing the ability to taper flutes along the length ofthe flute without creating a strain in the media. As a result of this,the flute shapes referred to in FIGS. 5B and 5C can be referred to aszero strain flute shapes. Now referring to FIGS. 8 and 9A, the flutedsheet 122 is shown in a tapered configuration. In FIG. 9A, the flutedsheet 122 is shown tapering from the configuration 122 a to theconfiguration 122 d. As a result of the taper, the fluted media includesthe configurations shown as 122 b and 122 c. As the fluted media tapersfrom 122 a to 122 d, the ridges 128 and the ridges 129 approach thelower peaks 126 and move away from the upper peaks 125. Accordingly, asthe fluted media 122 tapers from 122 a to 122 d, the cross sectionalsurface area between the fluted sheet 122 and the facing sheet 123decreases. Corresponding with this decrease in cross sectional surfacearea, the corresponding flutes formed by the fluted sheet 122 and afacing sheet contacting the upper peaks 125 experience an increase incross sectional surface area. It is additionally observed that as thetaper moves toward the end configurations shown at 122 a and 122 d, theridges tend to merge together or become less distinguishable from eachother. The configuration shown at 122 a tends to look more like the lowcontact shape. In addition, it is seen that as the fluted media tapersfrom 122 d to 122 a, the ridges 128 and the ridges 129 approach theupper peaks 125. In the case of the tapered zero-strain shapes, thefluted sheet can be characterized as having multiple ridges betweenadjacent peaks over at least 30%, and preferably at least 50%, of thelength of the flute.

An advantage of using the filtration media 120 where the fluted sheet122 contains ridges 128 and ridges 129 is the ability to taper theflutes without creating excessive strain, and the ability to usefiltration media that need not exhibit a strain greater than 12%. Ingeneral, strain can be characterized by the following equation:

$\text{strain} = {\frac{{D\; 2\max} - {D\; 2\min}}{D\; 2\min} \times 100}$

D2 min refers to the media distance where the media is relaxed orwithout strain, and D2 max refers to the media distance under strain ata point prior to tear. Filtration media that can withstand a strain ofup to about 12% without ripping or tearing is fairly commonly used inthe filtration industry. Commonly used filtration media can becharacterized as cellulosic based. In order to increase the strain thatthe media can withstand, synthetic fibers can be added to the media. Asa result, it can be fairly expensive to use media that must withstand astrain greater than 12%. Accordingly, it is desirable to utilize a fluteconfiguration that provides for tapering of the flute while minimizingthe strain on the media, and avoiding the necessity of using expensivemedia that can tolerate higher strains than 12%.

Now referring to FIGS. 9B′, 9B″, and 9B′″, the fluted sheet 142 of FIG.5C is shown in a tapered configuration extending from locations 142 a to142 b, and then to 142 c. As the flute tapers to a smallercross-sectional area (the area between the fluted sheet 142 and thefacing sheet 143), the ridges 148 and 149 move toward the peak 145. Thereverse can also be said. That is, as the cross-sectional area in theflute increases, the ridges 148 and 149 move toward the peak 144.

The flute shapes exemplified in FIGS. 5A-C can help provide for reducingthe area of media that may become masked at the peaks compared withstandard A and B fluted media. In addition, the shapes exemplified inFIGS. 5A-C can help assist in increasing the amount of media availablefor filtration compared with standard A and B fluted media. In FIG. 5A,viewing the fluted media 112 from the facing sheet 113, the ridges 118can be seen to provide the flute with a concave appearance. From theperspective of facing sheet 111, the ridges 118 can be seen to providethe media extending between adjacent peaks with a convex appearance. Nowreferring to FIG. 5B, the ridges 128 and 129 can be seen as providingboth a concave and a convex appearance from either side of the flutedmedia 122 from peak to adjacent peak. It should be appreciated that theflutes are not actually concave or convex in view of the presence of theridges. Accordingly, the ridges provide a transition or discontinuity inthe curve. Another way of characterizing the presence of the ridge is byobserving a discontinuity in the curve of the media wherein thediscontinuity is not present in standard A flutes and B flutes.Furthermore, it should be appreciated that the flute shapes depicted inFIGS. 5A-5C and 9A-9B′″ are somewhat exaggerated. That is, after formingthe fluted media, there will likely be a degree of spring or memory inthe media that causes it to bow out or curve. Furthermore, theapplication of fluid (e.g., air) through the media may cause the mediato deflect. As a result, the actual media prepared according to thisdescription will not necessarily follow precisely along the drawingspresented in FIGS. 5A-5C and 9A-9B′″.

The single facer media configurations shown in FIGS. 5A-5C can bereversed, if desired. For example, the single facer media 117 includesthe fluted sheet 112 and the facing sheet 113. If desired, the singlefacer media can be constructed so that it includes the fluted sheet 112and the facing sheet 111. Similarly, the single facer media shown inFIGS. 5B and 5C can be reversed, if desired. The characterization of thesingle facer media shown in FIGS. 5A-5C is provided for purposes ofexplaining the invention. One will understand that a single facer mediacan be prepared by combining the fluted sheet with a facing sheet in amanner essentially opposite of that depicted in FIGS. 5A-5C. That is,after the step of fluting the fluted sheet, the fluted sheet can becombined with a facing sheet on either side of the fluted sheet.

Flute Volume Asymmetry

Flute volume asymmetry refers to a volumetric difference within a filterelement or filter cartridge between the upstream volume and thedownstream volume. The upstream volume refers to the volume of the mediathat receives the unfiltered fluid (e.g., air), and the downstreamvolume refers to the volume of the media that receives the filteredfluid (e.g., air). Filter elements can additionally be characterized ashaving a dirty side and a clean side. In general, the dirty side offiltration media refers to the volume of media that receives theunfiltered fluid. The clean side refers to the volume of media thatreceives the filtered fluid that has passed via filtering passage fromthe dirty side. It can be desirable to provide a media having a dirtyside or upstream volume that is greater than the clean side ordownstream volume. It has been observed that in the case of filteringair, particulates in the air are deposited on the dirty side and, as aresult, the capacity of the filtration media can be determined by thevolume of the dirty side. By providing volume asymmetry, it is possibleto increase the volume of the media available for receiving the dirtyair and thereby increase the capacity of the media pack.

Filtration media having a flute volume asymmetry exists when thedifference between the upstream volume and the downstream volume isgreater than 10%. Filtration media have a flute volume asymmetry can bereferred to as a media pack having an asymmetric volume arrangement.Flute volume asymmetry can be expressed by the following formula:

$\text{volume~~asymmetry} = \frac{{volume}_{upstream} - {{volume}_{downstream} \times 100}}{{volume}_{downstream}}$

Preferably, media exhibiting volume asymmetry has volume asymmetry ofgreater than about 10%, greater than about 20%, greater than 30%, andpreferably greater than about 50%. Exemplary ranges for flute volumeasymmetry include about 30% to about 250%, and about 50% to about 200%.In general, it may be desirable for the upstream volume to be greaterthan the downstream volume when it is desirable to maximize the life ofthe media. Alternatively, there may be situations where it is desirableto minimize the upstream volume relative to the downstream volume. Forexample, in the case of a safety element, it may be desirable to providea safety element having a relatively low upstream volume so that themedia fills and prevents flow relatively quickly as an indicator thatfailure has occurred in an upstream filter element.

The volume asymmetry can be calculated by measuring the cross-sectionalsurface area of flutes from a photograph showing a sectional view of theflutes. If the flutes form a regular pattern, this measurement willyield the flute volume asymmetry. If the flutes are not regular (e.g.,tapered), then one can take several sections of the media and calculatethe flute volume asymmetry using accepted interpolation or extrapolationtechniques.

Flute design can be adjusted to provide a flute asymmetry that enhancesfiltration. In general, flute asymmetry refers to forming flutes havingnarrower peaks and widened arching troughs, or vice versa so that theupstream volume and downstream volume for the media are different. Anexample of asymmetric volume arrangement is provided in U.S. PatentApplication Publication No. US 2003/0121845 to Wagner et al. Thedisclosure of U.S. Patent Application Publication No. US 2003/0121845 isincorporated herein by reference.

Now referring to FIGS. 10A and 10B, asymmetric flutes volumes are shownby the filtration media 150 and 160 where FIGS. 10A and 10B aresectional views of, for example, regular non-tapered fluted media. Thefiltration media 150 shows a fluted sheet 152 between facing sheets 154and 155. The fluted sheet 152 is configured to provide a greater volumebetween the fluted sheet 152 and the facing sheet 154 than the volumedefined by the fluted sheet 152 and the facing sheet 155. As a result,the volume defined by the area between the fluted sheet 152 and thefacing sheet 154 can be provided as the upstream volume or as the dirtyside volume when it is desired to maximize the upstream volume or dirtyside volume. The flute filtration media 160 shows a fluted sheet 162between facing sheets 164 and 165. The fluted sheet is configured toprovide a greater volume between the fluted sheet 162 and the facingsheet 165. The area between the flutes sheet 162 and the facing sheet165 can be characterized, if desired, as the upstream volume or thedirty side volume.

Filtration media having an asymmetric volume arrangement can result fromthe presence of regular flutes or tapered flutes. Furthermore, mediahaving relatively symmetric tapered flutes (e.g., flutes tapering ineach direct to relatively the same extent), can provide media having alack of an asymmetric volume arrangement (less than 10% volumeasymmetry). Accordingly, the existence or non-existence of taperedflutes does not imply or mean that existence or non-existence of anasymmetric volume arrangement. Media having a regular flute arrangement(e.g., non-tapered) may or may not exhibit an asymmetric volumearrangement.

The media pack can be provided so that flutes within the media pack areboth regular and tapered. For example, the flutes can be provided sothat along the length of the flute, the flute at one portion of thelength is tapered and at another portion of the length is regular. Anexemplary arrangement include, for example, a taper-straight-taperarrangement where the flute tapers from one face to a predeterminedlocation and then exhibits a regular arrangement until anotherpredetermined location and then exhibits a taper. The existence of ataper-straight-taper arrangement can be used to help provide volumeasymmetry, and can be used to help handle loading and pressure drop.

Darted Flutes

FIGS. 11-18 illustrate a technique for closing an end of a flute havinga curved wave pattern. The technique can be referred to as darting andgeneral techniques for darting flutes are described in U.S. PatentPublication No. US 2006/0163150 that published on Jul. 27, 2006. Theentire disclosure of U.S. Patent Publication No. US 2006/0163150 isincorporated herein by reference.

An exemplary darting technique that can be used to close flutes infiltration media according to the invention is shown in FIGS. 11-18.Although the darting technique provided in FIGS. 11-18 is shown in thecontext prior art media, the darting technique can be applied to flutedmedia according to the present invention. For example, the fluted mediashown in FIGS. 5A-C can be darted according to the technique shown inFIGS. 11-18.

In general, darting can occur to provide closure after a facer bead 190is applied for securing a fluted sheet 204 to a facer sheet 206. Ingeneral, and as described in U.S. Patent Publication No. US2006/0163150, an indenting or darting wheel can be used to form theflutes 200 as shown in FIGS. 11-13, and a folder wheel can be used toclose the flutes 200 as shown in FIGS. 14-18. As shown in FIGS. 11-13,the darting wheel deforms a portion 202 of the upper peak 204, byindenting or inverting it. By “inverting” and variants thereof, it ismeant that the upper peak 204 is indented or turned inward in adirection toward the facing sheet 206. FIG. 12 is a cross-sectional viewalong the mid-point of the inversion 210 created by the darting wheel.The inversion 210 is between a pair of peaks 212, 214 that are createdas a result of the darting process. The peaks 212, 214 together form aflute double peak 216. The peaks 212, 214 in the flute double peak 216have a height that is shorter than the height of the upper peak 204before inversion. FIG. 13 illustrates the cross-section of the flute 200at a portion of the flute 200 that did not engage the darting wheel, andthus was not deformed. As can be seen in FIG. 13, that portion of theflute 200 retains its original shape.

While the flute double peak 216 shown in FIG. 12 represents an indentingof the upper peak 204 to form a pair of peaks 212 and 214 that areessentially symmetrical, it should be understood that the preciselocation of the darting or indenting may be off center. As a result ofthe timing of the indenting or darting wheel and the flexibility of themedia, the peaks 212 and 214 may have different sizes, and the relativesize of the peaks 212 and 214 can vary across the media from flute toflute.

Attention is now directed to FIGS. 14-18. FIGS. 14-18 show sections ofthe darted section 198 after engagement with the folder wheel. FIG. 18,in particular, shows an end view of the darted section 198, incross-section. A fold arrangement 218 can be seen to form a darted flute220 with four creases 221 a, 221 b, 221 c, 221 d. The fold arrangement218 includes a flat first layer 222 that is secured to the facing sheet64. A second layer 224 is shown pressed against the flat first layer222. The second layer 224 is preferably formed from folding oppositeouter ends 226, 227 of the first layer 222.

Still referring to FIG. 18, two of the folds or creases 221 a, 221 bwill generally be referred to herein as “upper, inwardly directed” foldsor creases. The term “upper” in this context is meant to indicate thatthe creases lie on an upper portion of the entire fold 220, when thefold 220 is viewed in the orientation of FIG. 11. The term “inwardlydirected” is meant to refer to the fact that the fold line or creaseline of each crease 221 a, 221 b, is directed toward the other.

In FIG. 18, creases 221 c, 221 d, will generally be referred to hereinas “lower, outwardly directed” creases. The term “lower” in this contextrefers to the fact that the creases 221 c, 221 d are not located on thetop as are creases 221 a, 221 b, in the orientation of FIG. 14. The term“outwardly directed” is meant to indicate that the fold lines of thecreases 221 c, 221 d are directed away from one another.

The terms “upper” and “lower” as used in this context are meantspecifically to refer to the fold 220, when viewed from the orientationof FIG. 18. That is, they are not meant to be otherwise indicative ofdirection when the fold 120 is oriented in an actual product for use.

Based upon these characterizations and review of FIG. 18, it can be seenthat a preferred regular fold arrangement 218 according to FIG. 18 inthis disclosure is one which includes at least two “upper, inwardlydirected, creases.” These inwardly directed creases are unique and helpprovide an overall arrangement at which the folding does not cause asignificant encroachment on adjacent flutes. These two creases result inpart from folding tips 212, 214, FIG. 18, toward one another.

A third layer 228 can also be seen pressed against the second layer 224.The third layer 228 is formed by folding from opposite inner ends 230,231 of the third layer 228. In certain preferred implementations, thefacing sheet 206 will be secured to the fluted sheet 196 along the edgeopposite from the fold arrangement 218.

Another way of viewing the fold arrangement 218 is in reference to thegeometry of alternating peaks 204 and troughs 205 of the corrugatedsheet 196. The first layer 222 includes the inverted peak 210. Thesecond layer 224 corresponds to the double peak 216 that is foldedtoward, and in preferred arrangements, folded against the inverted peak210. It should be noted that the inverted peak 210 and the double peak216, corresponding to the second layer 224, is outside of the troughs205 on opposite sides of the peak 204. In the example shown, there isalso the third layer 228, which extends from folded over ends 230, 231of the double peak 216.

FIGS. 15-17 show the shape of the flute 200 at different sections. FIG.17 shows an undeformed section of the flute 200. The inversion 210 canbe seen in FIGS. 15 and 16 extending along from where it engages thefacing sheet 206 (FIG. 18) to a point where it no longer exists (FIG.17). In FIGS. 15 and 16, the inversion 210 is spaced at differentlengths from the facing sheet 206.

Although the flute closure shown in FIG. 18 represents a closureresulting from a darting of the upper peak 204 to form relativelysymmetrical peaks 212 and 214, it should be understood that theresulting closure may look different if the indenting of the upper peak204 occurs at a location off center. The resulting closure may not be assymmetrical as the closure shown in FIG. 18. The fold arrangement may beprovided so that only one of the fold tips is folded over.

A process used to provide a dart according to FIGS. 1-18 can be referredto as “center indenting,” “center inverting,” “center darting” or“center deformation.” By the term “center” in this context, again, it ismeant that the indentation or inversion occurred at an apex or center ofthe associated upper peak 80, engaged by the indenting or darting wheel.A deformation or indent will typically be considered herein to be acenter indent, as long as it occurs within 3 mm of the center of aridge. In the context of darting, the term “crease,” “fold,” or “foldline” are meant to indicate an edge formed by folding the media back onor over itself, with or without sealant or adhesive between portions ofthe media.

While the closure technique described in the context of FIGS. 11-18 canresult in a flute closure as shown in FIG. 18, it is possible thatduring darting, as a result of the flexibility of the media and thespeed at which the media is moving, the step of indenting may not occurprecisely at the apex or peak of the corrugated sheet 196. As a result,folding of the tips 112 and 114 may not be as symmetrical as shown. Infact, one of the tips 212 and 214 may become somewhat flattened whilethe other tip is folded. Furthermore, in certain flute designs, it maybe desirable to skip the indenting step. For example, the flute mighthave a height (J) that is sufficiently small so that the flute can bepressed closed to provide a repeating fold pattern without requiring astep of indenting the flute tip.

Plug Length and Flute Height

Z-media is sometimes characterized as having flutes extending from aninlet face to an outlet face of the media, and a first portion of theflutes can be characterized as inlet flutes and a second portion of theflutes can be characterized as outlet flutes. The inlet flutes can beprovided with a plug or seal near or at the outlet face. Furthermore,the outlet flutes can be provided with a plug or seal near or at theinlet face. Of course, alternatives of this arrangement are available.For example, the seals or plugs need not be provided at or adjacent tothe inlet face or outlet face. The seals or plugs can be provided awayfrom the inlet face or the outlet face, if desired. In the case of hotmelt adhesive being used as a seal or plug, it is often found that theplug has a length of at least about 12 mm in standard B fluted media.The plug length can be measured from the face of the element to theinner surface of the plug. The applicants have found that by reducingthe plug length, it is possible to provide desirable characteristics ofthe filtration media including increased loading capacity, lower initialpressure drop, increased surface area of media available for filtration,reduced the amount of filtration media needed for a filter element, orcombinations thereof. It can be desirable to provide a plug length thatis less than about 10 mm, less than about 8 mm, less than about 7 mm,and even more preferably less than about 6 mm. Reducing the plug lengthcan provide increased performance in the situation where the flutelength is relatively short (e.g., a flute length of less than about 5inches). Decreasing the plug length for a relatively long flute length(e.g., greater than 8 inches) may not be as effective for enhancingperformance compared with reducing plug length for media having ashorter flute length. For shorter length flutes, for example, fluteshaving a length of less than about 5 inches (e.g., about 2 inches toabout 4 inches), reducing the plug length to less than about 7 mm orless than about 6 mm can provide enhanced performance. The plug lengthcan be referred to as an average plug length, and can be measured as theaverage plug length of the plugs sealing the first plurality of flutesor sealing the second plurality of flutes or both. That is, the averageplug length can be reduced for the plugs present at or near one of thefaces of the media pack. There is no requirement that the average pluglength is an average plug length for all seals within the media pack.That is, the average plug length for the first portion of flutes can bedifferent from the plug length for the second portion of flutes. Theaverage plug length can be provided as an average plug length for all ofthe seals (e.g., for the first plurality of flutes and for the secondplurality of flutes), if desired.

An exemplary technique for reducing plug length is to trim the edge ofthe single facer that contains sealant or adhesive holding the flutedsheet to the facing sheet as a way to reduce the plug length. That is,the width of single facer during production can be longer than necessarywith the understanding that the width of the single facer will betrimmed to reduce the plug length. In addition, the plug length can bereduced by trimming one or both faces of the media. An alternativetechnique for reducing plug length is to use a thicker or more viscoussealant material to provide a seal or plug having a shorter length.

The flute height (J) can be selected depending upon the desired fluteheight or flute size for the resulting filtration media. The conditionsof use for the filtration media can be relied upon to select the desiredflute height (J). In the case where a filter element utilizing the mediaaccording to the present invention is used as a substitute for aconventional filter element that utilizes, for example, a standard Bflute, the height J can be about 0.075 inch to about 0.150 inch. In thecase where a filter element utilizing the media according to the presentinvention is used as a substitute for a conventional filter element thatutilizes, for example, a standard A flute, the height J can be about0.15 inch to about 0.25 inch.

Exemplary Media Definitions

In the case of z-media useful for air filtration applications, and inparticular for filtering an air stream for an internal combustionengine, the definition of the filtration media can be selected dependingupon whether the filtration media is intended maximize dust loadingcapacity, minimize pressure drop, or provide a desirable level of bothcapacity and pressure drops. The dust loading capacity can refer to thelife or longevity of the filtration media. Sometimes it is desirable todesign a filtration media that is capable of exhibiting a desired lifespan before it needs to be replaced. Alternatively, in certaincircumstances, it may be more desirable to design a filtration mediathat is capable of performing within a desired pressure drop range. Theselection of various definitions for the filtration media provides theflexibility for defining the filtration media for a particularenvironment and for a particular air cleaner. In addition, selecting thevarious definitions of the filtration media allows one to haveflexibility in designing an air cleaner to fit a particular environment.

The following described exemplary filtration media can be provided withor without the flute shape referred to earlier as “low contact” or “zerostrain.” The provision of a ridge or multiple ridges between peaks in afluted media is not a requirement of the filtration media, but can berelied upon for enhancing performance.

A first exemplary filtration media can be selected for maximizing dustloading capacity. The flute density can be selected so that it isgreater than the flute density of filter media prepared from Standard Bflute media. For example, the filtration media can be provided having aflute density of at least about 35.0 flute/inch², wherein the flutedensity is calculated according to the formula:

$\rho = \frac{\text{number~~of~~channels~~(open~~and~~closed)}}{2 \times z\text{-media~~pack~~cross sectional~~area}}$

wherein the number of channels is determined by counting the channels ina cross section of the media and the location where the media crosssectional area is determined. Preferably, the flute density can begreater than 45 flute/inch² or greater than about 50 flute/inch². Inorder to reduce pressure drop caused by the increase in flute density,the flute length can be decreased. For example, the media can beprovided having a flute length of less than 5 inches. Because of therelatively short flute length, the plug length can be provided asrelatively short in order to increase the amount of media available forfiltration. For example, the plugs can be provided having a length ofless than about 7 mm, and preferably less than about 6 mm. In addition,the flute volume asymmetry of the media can be adjusted. For example,the flute volume asymmetry of the media can be provided so that theupstream volume is at least 10 percent greater than the downstreamvolume. Preferably, the flute volume asymmetry can be greater than 30%,and preferably greater than 50%. The fluted media can be provided havinga flute width height ratio of at least about 2.7, and preferably atleast about 3.0.

A second exemplary media can be selected for providing a desired longlife. The second exemplary media can have a medium flute length. Forexample, the flute length can be about 5 inches to about 8 inches. Thesecond exemplary media can be provided without a taper, and can beprovided having a flute density of about 34 flutes/inch² which is aboutthe flute density of Standard B media. The second exemplary media can beprovided having a flute width height ratio of greater than about 2.7,and preferably greater than about 3.0. In addition, the second exemplarymedia can be provided having a flute volume asymmetry of greater than20%, and preferably greater than 30%.

A third exemplary filtration media can be provided so that the mediaexhibits a desired low pressure drop. The third exemplary filtrationmedia can have a relatively low flute density of less than about 34flute/inch², and preferably less than about 25 flute/inch². In addition,the flute length of the media can be medium length or long, and can havea length of at least about 5 inches and can have a length of about 6inches to about 12 inches. The third exemplary filtration media can beprovided with or without flute volume asymmetry. When provided withflute volume asymmetry, the media can have a flute volume asymmetry ofgreater than about 30%, or greater than about 70%. The flutes can beprovided as tapered or non-tapered.

A fourth exemplary filtration media can be provided to balance thedesired level of dust loading and the desired pressure drop. The fourthexemplary filtration media can be provided having relatively longflutes. For example, the flute length of the media can be about 8 inchesto about 12 inches. The fourth exemplary filtration media can beprovided with or without a taper.

Filter Elements

Now referring to FIGS. 19-28, filter elements are described that includea filtration media pack. The filtration media pack can be provided basedupon the media pack characterizations described herein, and based uponthe exemplary media definitions. One will understand how the filterelements shown in FIGS. 19-28 can be modified to accept the media ascharacterized herein. For example, the media can be provided as coiledor stacked, and can be provided having a flute length and flute densityrange as described. In addition, the filter elements shown in FIGS.19-20 are generally characterized as air filtration elements becausethey can be used to filter air.

The filtration media pack can be provided as part of a filter elementcontaining a radial seal as described in, for example, U.S. Pat. No.6,350,291, U.S. Patent Application No. US 2005/0166561, andInternational Publication No. WO 2007/056589, the disclosures of whichare incorporated herein by reference. For example, referring to FIG. 19,the filter element 300 includes filtration media pack 301 that can beprovided as a wound media pack 302 of single facer media, and caninclude a first face 304 and a second face 306. A frame 308 can beprovided on a first end of the media pack 310, and can extend beyond thefirst face 304. Furthermore, the frame 308 can include a step orreduction in circumference 312 and a support 314 that extends beyond thefirst face 304. A seal member 316 can be provided on the support 314.When the filter element 301 is introduced within the housing 320, theseal member 316 engages the housing sealing surface 322 to provide aseal so that unfiltered air does not bypass the filtration media pack300. The seal member 316 can be characterized as a radial seal becausethe seal member 316 includes a seal surface 317 that engages the housingsealing surface 322 in a radial direction to provide sealing. Inaddition, the frame 308 can include a media pack cross brace or supportstructure 324 that helps support the frame 308 and helps reducetelescoping of the air filtration media pack 300. An access cover 324can be provided for enclosing the filter element 300 within the housing320.

The filtration media pack can be provided as part of a filter elementhaving a variation on the radial seal configuration. As shown in FIG.20, the seal 330 can be relied upon for holding the frame 332 to themedia pack 334. As shown in FIG. 19, the frame 308 can be adhesivelyattached to the media pack 301. As shown in FIG. 20, the frame 332 canbe provided adjacent to the first face 336 and the seal 330 can beprovided so that it holds the support 332 onto the media pack 334without the use of additional adhesive. The seal 330 can becharacterized as an overmold seal in that it expands along both sides ofthe seal support 338 and onto the outer surface of the media pack 334 atthe first end 340.

The filtration media pack can be provided as part of a filter elementaccording to U.S. Pat. No. 6,235,195, the entire disclosure of which isincorporated herein by reference. Now referring to FIG. 21, the filterelement 350 includes a wound media pack 352 having an oblong orracetrack shape, and an axial pinch seal 354 attached to the end andcircumscribing the exterior of the media pack. The axial pinch seal 354is shown provided between the first face 356 and the second face 358 ofthe media pack. The axial pinch seal 354 includes a base portion 360 anda flange portion 362. The base portion 362 can be provided for attachingto the media pack. The flange portion 362 can be pinched between twosurfaces to create a seal. One of the surfaces can be a surface of thehousing that contains the filter element 350. In addition, the otherstructure that pinches the flange 362 can be an access cover or anotherstructure provided within the housing that helps maintain the seal sothat unfiltered air passes through the media pack without bypassing themedia pack. The filter element 350 can include a handle 364 extendingaxially from the first face 356. If desired, the handle can be providedextending axially from the second face 358. The handle 364 allows one topull or remove the filter element 350 from the housing.

Now referring to FIGS. 22-24, a filter element is shown at referencenumber 400. The filter element 400 includes a wound media pack 402, ahandle arrangement 404, and a seal arrangement 406. Details of thisfilter element construction can be found in U.S. Pat. No. 6,348,084, theentire disclosure of which is incorporated herein by reference. Thepreviously described single facer media can be used to prepare thefilter element 400.

The handle arrangement 404 includes a center board 408, handles 410, anda hook construction 412. The single facer media can be wound around thecenter board 408 so that the handles 410 extend axially from a firstface 414 of the media pack 402. The hook arrangement 412 can extend fromthe second face 416 of the media pack 402. The handles 410 allow anoperator to remove the filter element 400 from a housing. The hookconstruction 412 provides for attachment to a cross brace or supportstructure 420. The hook construction 412 includes hook members 422 and424 that engage the cross brace or support structure 420. The crossbrace or support structure 420 can be provided as part of a seal supportstructure 430 that extends from the second face 416 and includes a sealsupport member 432. A seal 434 can be provided on the seal supportmember to provide a seal between the filter element 400 and a housing.The seal 434 can be characterized as a radial seal when the seal isintended to provide sealing as a result of contact of a radially facingseal surface 436 and a housing seal surface.

The filtration media pack can be provided as part of a gas turbinesystem as shown in U.S. Pat. No. 6,348,085, the entire disclosure ofwhich is incorporated herein by reference. An exemplary gas turbinefiltration element is shown at reference number 450 in FIG. 25. Thefilter element 450 can include a primary filter element 452 and asecondary filter element 454. The secondary filter element 454 can bereferred to as a safety filter element. The main filter element 452 canbe provided as a filtration media pack as previously described in thisapplication. The filtration media pack can be provided as a result ofwinding a single facer media or as a result of stacking a single facermedia. The primary filter element 452 and the secondary filter element454 can be secured within a sleeve member 460. The sleeve member 460 caninclude a flange 462 that includes a seal 464. When installed, theelement 450 can be provided so that the flange 462 and seal 464 areprovided adjacent a support 466 and held in place by a clamp 200 so thatthe seal 464 provides a sufficient seal so that unfiltered air does notbypass the filter element 450.

Another filter element that can utilize the filtration media pack isdescribed in U.S. Pat. No. 6,610,126, the entire disclosure of which isincorporated herein by reference. Now referring to FIG. 26, the filterelement 500 includes a filtration media pack 502, a radial sealarrangement 504, and a dust seal or secondary seal arrangement 506. Thefilter element 500 can be provided within an air cleaner housing 510 andcan include, downstream of the filter element 500, a safety or secondaryfilter element 512. Furthermore, an access cover 514 can be provided forenclosing the housing 510. The housing 510 and the access cover 514 canpinch the dust seal 506 so that the dust seal 506 can be characterizedas a pinch seal.

The filtration media pack can be provided as a stacked media packarrangement according to International Publication No. WO 2006/076479and International Publication No. WO 2006/076456, the disclosures ofwhich are incorporated herein by reference. Now referring to FIG. 27, afilter element is shown at reference number 600 that includes a stacked,blocked, media pack 602. The blocked stacked media pack 602 can becharacterized as a rectangular or right (normal) parallelogram mediapack. To seal the opposite ends of the media pack 602 are positionedside panels 604 and 606. The side panels 604 and 606 seal the lead endand tail end of each stacked, single facer media. The media pack 602 hasopposite flow faces 610 and 612. It is pointed out that no flow pathbetween faces 610 and 612 is provided that does not also require the airto pass through media of the media pack 602 and thus to be filtered. Aperipheral, perimeter, housing seal ring 614 is positioned in the airfilter element 600. The particular seal ring 614 depicted is an axialpinch seal ring. If desired, a protective sheath or panel can beprovided over the media pack surfaces 626 and 622.

The filtration media pack can be provided as a stacked media packarrangement according to International Publication No. WO 2007/133635,the entire disclosure of which is incorporated herein by reference. Nowreferring to FIG. 28, a filter element is shown at reference number 650.The filter element 650 includes a stacked z-filter media arrangement 652having a first, in this instance, inlet face 654, and an oppositesecond, in this instance, outlet face 656. In addition, the filterelement 650 includes an upper side 660, a lower side 662, and oppositeside end 664 and 666. The stacked z-filter media arrangement 652generally comprises one or more stacks of strips of single facer mediawhere each strip comprises a fluted sheet secured to a facing sheet. Thestrips can be provided in a slanted arrangement. The strips areorganized with flutes extending between the inlet face 654 and theoutlet face 656. The filter element 650 depicted comprises a stackedz-filter media pack arrangement comprising two stacked media packsections 670 and 672. A seal member 680 can be molded to the media pack.

It should be appreciated that, in view of exemplary FIGS. 19-28, thatthe filtration media pack can be provided in various configurations toform filter elements that can then be used in various housingarrangements to provide enhanced performance.

Examples

Filter elements having media containing various flute designs werecompared using filter media performance modeling software. The filterelements were not constructed and tested for this example. Instead, thedimensions of the filter elements and the filter element components, theproperties and characteristics of the filter elements and the filterelement components, the conditions of use, and the characteristics ofthe air being filtered were inputted into a computer program that modelsfilter media performance. The filter media performance modeling softwarewas validated based upon tests run on actual Donaldson Company filtermedia. The results of the computer software modeling are expected tohave an error within about 10%. For the purpose of evaluating differentfilter media design alternatives, it is believed that an error value ofwithin about 10% is sufficiently low that the modeling software can beused to evaluate various design options. For purposes of the computermodeling software, the dust selected is characterized as SAE.

Tables 2-8 include a characterization of the filter element and thecomputer generated results. The tables identify the size of the elementevaluated using the filter media performance modeling software. Theelement size refers to the overall size of the element.

The filter elements characterized in each of the tables are stackedelements having a depth or flute length corresponding to the lastidentified dimension. For example, in Table 2(a), the element has a sizeof 8 inches×12 inches×5 inches where the flute length is 5 inches. Forelement 1, the flute type can be characterized as standard B. For runs 2and 3, the shape of the element has been changed while keeping thevolume of the element relatively constant. Beginning with element 4, theflute type can no longer be considered standard B, and is characterizedas arc-flat-are which generally describes a flute shape having arcsforming the internal peaks and the external peaks of a fluted sheet, anda relatively flat portion of media connecting an internal peak and anexternal peak. For elements 17-19, the flute type can be characterizedas low contact. The low contact shape is generally shown in FIG. 5A.

The filter elements in Tables 2-8 are additionally characterized by theflute density, volume asymmetry, flute width/height ratio, flute height,flute pitch, plug length, and media thickness. As a result of thisinformation, the computer modeling software calculates the initialpressure drop, the SAE fine loading to 12 inches water pressure drop,the volume, and the area of media required. These values are determinedfor a specified flow rate through the media. In addition, the tablesinclude comparisons with the base filter. In general, the base filterfor a table refers to the first listed element in that table. As aresult, performance changes can be evaluated among different elements asa result of changes to the design.

The general teaching demonstrated by the data in tables 2-8 is thatmultiple changes in the design of the filter element can significantlyimprove performance. In addition, single changes do not necessarilyprovide the large amounts of improvement compared with multiple changes.

TABLE 2(a) Density (flutes Flute Flute Initial Pressure per Width/Height Flute Pitch Plug Media Drop Element Size Flute Type square VolumeHeight (J) (D) Length Thickness (inches water Element (inches) Commentsand Size inch) Asymmetry Ratio (inches) (inches) (mm) (inches) gauge) 1 8 × 12 × 5 Standard B 34 0 2.5 0.103 0.258 12.7 0.0109 1.97 2  8.9 × 12× 4.5 change shape Standard B 34 0 2.5 0.103 0.258 12.7 0.0109 1.66 3 10× 12 × 4 change shape Standard B 34 0 2.5 0.103 0.258 12.7 0.0109 1.39 410 × 12 × 4 Arc-Flat-Arc 35 0 3.5 0.085 0.298 12.7 0.0109 1.49 5 10 × 12× 4 Arc-Flat-Arc 40 0 2.5 0.095 0.237 12.7 0.0109 1.47 6 10 × 12 × 4Arc-Flat-Arc 45 0 2.5 0.089 0.222 12.7 0.0109 1.54 7 10 × 12 × 4Arc-Flat-Arc 50 0 2.5 0.084 0.210 12.7 0.0109 1.62 8 10 × 12 × 4Arc-Flat-Arc 50 0 2.5 0.084 0.210 12.7 0.0109 1.62 9 10 × 12 × 4Arc-Flat-Arc 35 10 2.5 0.102 0.254 12.7 0.0109 1.42 10 10 × 12 × 4Arc-Flat-Arc 35 20 2.5 0.102 0.254 12.7 0.0109 1.44 11 10 × 12 × 4Arc-Flat-Arc 35 50 2.5 0.102 0.254 12.7 0.0109 1.59 12 10 × 12 × 4Arc-Flat-Arc 35 100 2.5 0.102 0.254 12.7 0.0109 1.98 13 10 × 12 × 4Arc-Flat-Arc 40 10 2.5 0.095 0.237 12.7 0.0109 1.49 14 10 × 12 × 4Arc-Flat-Arc 40 10 2.5 0.095 0.237 7 0.0109 1.49 15 10 × 12 × 4Arc-Flat-Arc 40 10 2.5 0.095 0.237 6 0.0109 1.49 16 10 × 12 × 4Arc-Rat-Arc 40 10 2.5 0.095 0.237 2 0.0109 1.49 17 10 × 12 × 4 LowContact 40 10 2.5 0.095 0.237 5 0.0109 1.42 18 10 × 12 × 4 Low Contact40 10 3 0.086 0.258 5 0.0109 1.49 19 10 × 12 × 4 Low Contact 40 10 0.330.270 0.089 5 0.0109 1.78

TABLE 2(b) % of Initial Pressure Drop of SAE Fine Loading to Media Base12 inches H2O % Loading % Volume of Required % Area of Flow Rate ElementFilter Pressure Drop (grams) of Base Filter Volume Base Filter (ft²)Base Filter (cfm) 1 100%  603 100% 480 100% 63.6 100% 636 2 84% 589  98%480 100% 63.9 100% 636 3 71% 561  93% 480 100% 64.0 101% 636 4 76% 714118% 480 100% 71.3 112% 636 5 75% 611 101% 480 100% 68.9 108% 636 6 78%645 107% 480 100% 73.0 115% 636 7 82% 672 111% 480 100% 76.9 121% 636 882% 672 111% 480 100% 76.9 121% 636 9 72% 555  92% 480 100% 64.9 102%636 10 73% 563  93% 480 100% 64.8 102% 636 11 81% 561  93% 480 100% 65.0102% 636 12 101%  542  90% 480 100% 65.5 103% 636 13 76% 599  99% 480100% 69.1 109% 636 14 76% 741 123% 480 100% 69.1 109% 636 15 76% 779129% 480 100% 69.1 109% 636 16 76% 814 135% 480 100% 69.1 109% 636 1772% 1017 169% 480 100% 67.9 107% 636 18 76% 1131 188% 480 100% 71.7 113%636 19 90% 1351 224% 480 100% 82.3 129% 636

TABLE 3(a) Density Flute Flute Initial Element (flutes Width/ HeightFlute Plug Media Pressure Drop Size Flute Type per square Volume Height(J) Pitch (D) Length Thickness (inches water Element (inches) Commentsand Size inch) Asymmetry Ratio (inches) (inches) (mm) (inches) gauge) 2010 × 12 × 4 Arc-Flat-Arc 40 20 2.5 0.095 0.237 12.7 0.0109 1.51 21 10 ×12 × 4 Arc-Flat-Arc 40 20 2.5 0.095 0.237 7 0.0109 1.51 22 10 × 12 × 4Arc-Flat-Arc 40 20 2.5 0.095 0.237 6 0.0109 1.51 23 10 × 12 × 4Arc-Flat-Arc 40 20 2.5 0.095 0.237 5 0.0109 1.51 24 10 × 12 × 4 LowContact 40 20 2.5 0.095 0.237 5 0.0109 1.45 25 10 × 12 × 4 Low Contact40 20 3 0.086 0.258 5 0.0109 1.52 26 10 × 12 × 4 Low Contact 40 20 0.330.270 0.089 5 0.0109 1.81 27 10 × 12 × 4 Arc-Flat-Arc 40 50 2.5 0.0950.237 12.7 0.0109 1.67 28 10 × 12 × 4 Arc-Flat-Arc 40 50 2.5 0.095 0.2377 0.0109 1.66 29 10 × 12 × 4 Arc-Flat-Arc 40 50 2.5 0.095 0.237 6 0.01091.66 30 10 × 12 × 4 Arc-Flat-Arc 40 50 2.5 0.095 0.237 5 0.0109 1.66 3110 × 12 × 4 Low Contact 40 50 2.5 0.095 0.237 5 0.0109 1.60 32 10 × 12 ×4 Low Contact 40 50 3 0.086 0.258 5 0.0109 1.67 33 10 × 12 × 4 LowContact 40 50 0.33 0.270 0.089 5 0.0109 1.98 34 10 × 12 × 4 Arc-Flat-Arc40 100 2.5 0.095 0.237 12.7 0.0109 2.08 35 10 × 12 × 4 Arc-Flat-Arc 40100 2.5 0.095 0.237 7 0.0109 2.07 36 10 × 12 × 4 Arc-Flat-Arc 40 100 2.50.095 0.237 6 0.0109 2.07 37 10 × 12 × 4 Arc-Flat-Arc 40 100 2.5 0.0950.237 5 0.0109 2.07 38 10 × 12 × 4 Low Contact 40 100 2.5 0.095 0.237 50.0109 2.00 39 10 × 12 × 4 Low Contact 40 100 3 0.086 0.258 5 0.01092.09 40 10 × 12 × 4 Low Contact 40 100 0.33 0.270 0.089 5 0.0109 2.41

TABLE 3(b) SAE Fine Loading % of Initial to 12 inches H2O Media PressureDrop Pressure Drop % Loading % Volume of Required % Area of Flow RateElement of Base Filter (grams) of Base Filter Volume Base Filter (ft²)Base Filter (cfm) 20  77% 613 102% 480 100% 69.0 108% 636 21  77% 764127% 480 100% 69.0 108% 636 22  77% 798 132% 480 100% 69.0 108% 636 23 77% 838 139% 480 100% 69.0 108% 636 24  74% 1047 174% 480 100% 68.1107% 636 25  77% 1158 192% 480 100% 71.9 113% 636 26  92% 1376 228% 480100% 83.3 131% 636 27  85% 608 101% 480 100% 69.2 109% 636 28  84% 764127% 480 100% 69.2 109% 636 29  84% 799 133% 480 100% 69.2 109% 636 30 84% 842 140% 480 100% 69.2 109% 636 31  81% 1119 186% 480 100% 68.8108% 636 32  85% 1237 205% 480 100% 72.5 114% 636 33 101% 1426 236% 480100% 83.7 132% 636 34 106% 588  98% 480 100% 69.9 110% 636 35 105% 735122% 480 100% 69.9 110% 636 36 105% 778 129% 480 100% 69.9 110% 636 37105% 818 136% 480 100% 69.9 110% 636 38 102% 1186 197% 480 100% 70.5111% 636 39 106% 1292 214% 480 100% 74.0 116% 636 40 122% 1441 239% 480100% 83.7 132% 636

TABLE 4(a) Density (flutes Flute Flute Flute per Width/ Height PitchPlug Media Initial Pressure Element Size Flute Type and square VolumeHeight (J) (D) Length Thickness Drop (inches water Element (inches)Comments Size inch) Asymmetry Ratio (inches) (inches) (mm) (inches)gauge) 41  8 × 12 × 5 Standard B Flute 34 0 2.5 0.103 0.258 12.7 0.01090.96 42  8.9 × 12 × 4.5 Arc-Flat-Arc 34 0 2.5 0.103 0.258 12.7 0.01090.82 43 10 × 12 × 4 Arc-Flat-Arc 34 0 2.5 0.103 0.258 12.7 0.0109 0.7044 10 × 12 × 4 Arc-Flat-Arc 35 0 3.5 0.085 0.298 12.7 0.0109 0.75 45 10× 12 × 4 Arc-Flat-Arc 40 0 2.5 0.095 0.237 12.7 0.0109 0.74 46 10 × 12 ×4 Arc-Flat-Arc 45 0 2.5 0.089 0.222 12.7 0.0109 0.78 47 10 × 12 × 4Arc-Flat-Arc 50 0 2.5 0.084 0.210 12.7 0.0109 0.83 48 10 × 12 × 4Arc-Flat-Arc 50 0 2.5 0.084 0.210 12.7 0.0109 0.83 49 10 × 12 × 4Arc-Flat-Arc 35 10 2.5 0.102 0.254 12.7 0.0109 0.72 50 10 × 12 × 4Arc-Flat-Arc 35 20 2.5 0.102 0.254 12.7 0.0109 0.73 51 10 × 12 × 4Arc-Flat-Arc 35 50 2.5 0.102 0.254 12.7 0.0109 0.79 52 10 × 12 × 4Arc-Flat-Arc 35 100 2.5 0.102 0.254 12.7 0.0109 0.98 53 10 × 12 × 4Arc-Flat-Arc 40 10 2.5 0.095 0.237 12.7 0.0109 0.75 54 10 × 12 × 4Arc-Flat-Arc 40 10 2.5 0.095 0.237 7 0.0109 0.75 55 10 × 12 × 4Arc-Flat-Arc 40 10 2.5 0.095 0.237 6 0.0109 0.75 56 10 × 12 × 4Arc-Flat-Arc 40 10 2.5 0.095 0.237 5 0.0109 0.75 57 10 × 12 × 4 LowContact 40 10 2.5 0.095 0.237 5 0.0109 0.71 58 10 × 12 × 4 Low Contact40 10 3 0.086 0.258 5 0.0109 0.75 59 10 × 12 × 4 Low Contact 40 10 0.330.270 0.089 5 0.0109 0.91

TABLE 4(b) SAE Fine Loading % of Initial to 12 inches H2O % MediaPressure Drop Pressure Drop % Loading Volume of Required % Area of FlowRate Element of Base Filter (grams) of Base Filter Volume Base Filter(ft²) Base Filter (cfm) 41 49% 1038 172% 480 100% 63.6 100% 400 42 42%1012 168% 480 100% 63.9 100% 400 43 36% 965 160% 480 100% 64.0 101% 40044 38% 1133 188% 480 100% 71.3 112% 400 45 38% 1020 169% 480 100% 68.9108% 400 46 40% 1055 175% 480 100% 73.0 115% 400 47 42% 1081 179% 480100% 76.9 121% 400 48 42% 1081 179% 480 100% 76.9 121% 400 49 37% 975162% 480 100% 64.9 102% 400 50 37% 997 165% 480 100% 64.8 102% 400 5140% 1020 169% 480 100% 65.0 102% 400 52 50% 1041 173% 480 100% 65.5 103%400 53 38% 1024 170% 480 100% 69.1 109% 400 54 38% 1022 169% 480 100%69.1 109% 400 55 38% 1272 211% 480 100% 69.1 109% 400 56 38% 1322 219%480 100% 69.1 109% 400 57 36% 1533 254% 480 100% 67.9 107% 400 58 38%1627 270% 480 100% 71.7 113% 400 59 46% 1780 295% 480 100% 82.3 129% 400

TABLE 5(a) Flute Flute Element Density Width/ Height Flute Plug MediaInitial Pressure Size Flute Type (flutes per Volume Height (J) Pitch (D)Length Thickness Drop (inches water Element (inches) Comments and Sizesquare inch) Asymmetry Ratio (inches) (inches) (mm) (inches) gauge) 6010 × 12 × 4 Arc-Flat-Arc 40 20 2.5 0.095 0.237 12.7 0.0109 0.76 61 10 ×12 × 4 Arc-Flat-Arc 40 20 2.5 0.095 0.237 7 0.0109 0.76 62 10 × 12 × 4Arc-Flat-Arc 40 20 2.5 0.095 0.237 6 0.0109 0.76 63 10 × 12 × 4Arc-Flat-Arc 40 20 2.5 0.095 0.237 5 0.0109 0.76 64 10 × 12 × 4 LowContact 40 20 2.5 0.095 0.237 5 0.0109 0.72 65 10 × 12 × 4 Low Contact40 20 3 0.086 0.258 5 0.0109 0.76 66 10 × 12 × 4 Low Contact 40 20 0.330.270 0.089 5 0.0109 0.92 67 10 × 12 × 4 Arc-Flat-Arc 40 50 2.5 0.0950.237 12.7 0.0109 0.83 68 10 × 12 × 4 Arc-Flat-Arc 40 50 2.5 0.095 0.2377 0.0109 0.83 69 10 × 12 × 4 Arc-Flat-Arc 40 50 2.5 0.095 0.237 6 0.01090.83 70 10 × 12 × 4 Arc-Flat-Arc 40 50 2.5 0.095 0.237 5 0.0109 0.83 7110 × 12 × 4 Low Contact 40 50 2.5 0.095 0.237 5 0.0109 0.79 72 10 × 12 ×4 Low Contact 40 50 3 0.086 0.258 5 0.0109 0.84 73 10 × 12 × 4 LowContact 40 50 0.33 0.270 0.089 5 0.0109 1.01 74 10 × 12 × 4 Arc-Flat-Arc40 100 2.5 0.095 0.237 12.7 0.0109 1.03 75 10 × 12 × 4 Arc-Flat-Arc 40100 2.5 0.095 0.237 7 0.0109 1.03 76 10 × 12 × 4 Arc-Flat-Arc 40 100 2.50.095 0.237 6 0.0109 1.03 77 10 × 12 × 4 Arc-Flat-Arc 40 100 2.5 0.0950.237 5 0.0109 1.03 78 10 × 12 × 4 Low Contact 40 100 2.5 0.095 0.237 50.0109 0.99 79 10 × 12 × 4 Low Contact 40 100 3 0.086 0.258 5 0.01091.04 80 10 × 12 × 4 Low Contact 40 100 0.33 0.270 0.089 5 0.0109 1.22

TABLE 5(b) SAE Fine % of Initial Loading to 12 Pressure inches H2O MediaDrop of Base Pressure Drop % Loading % Volume of Required % Area of FlowRate Element Filter (grams) of Base Filter Volume Base Filter (ft²) BaseFilter (cfm) 60 39% 1059 176% 480 100% 69.0 108% 400 61 39% 1263 209%480 100% 69.0 108% 400 62 39% 1313 218% 480 100% 69.0 108% 400 63 39%1364 226% 480 100% 69.0 108% 400 64 37% 1585 263% 480 100% 68.1 107% 40065 39% 1683 279% 480 100% 71.9 113% 400 66 47% 1830 303% 480 100% 83.3131% 400 67 42% 1087 180% 480 100% 69.2 109% 400 68 42% 1303 216% 480100% 69.2 109% 400 69 42% 1357 225% 480 100% 69.2 109% 400 70 42% 1412234% 480 100% 69.2 109% 400 71 40% 1715 284% 480 100% 68.8 108% 400 7243% 1816 301% 480 100% 72.5 114% 400 73 51% 1950 323% 480 100% 83.7 132%400 74 52% 1103 183% 480 100% 69.9 110% 400 75 52% 1334 221% 480 100%69.9 110% 400 76 52% 1398 232% 480 100% 69.9 110% 400 77 52% 1453 241%480 100% 69.9 110% 400 78 50% 1870 310% 480 100% 70.5 111% 400 79 53%1967 326% 480 100% 74.0 116% 400 80 62% 2086 346% 480 100% 83.7 132% 400

TABLE 6(a) Element Flute Flute Plug Media Initial Pressure % of InitialSize Flute Type Height (J) Width/Height Length Thickness Drop (inchesPressure Drop of Element (inches) Comments and Size (inches) Ratio (mm)(inches) H2O) Base Filter 81 8 × 12 × 6 Standard B 0.103 2.45 12.70.0109 1.99 100 82 8 × 12 × 8 Standard B 0.103 2.45 12.7 0.0109 2.06 10083 8 × 12 × 6 Low Contact 0.103 2.50 12.7 0.0109 2.15 108.0 84 8 × 12 ×8 Low Contact 0.103 2.50 12.7 0.0109 2.20 106.8 85 8 × 12 × 6 LowContact 0.103 3.50 12.7 0.0109 1.84 92.5 86 8 × 12 × 8 Low Contact 0.1033.50 12.7 0.0109 1.88 91.3 87 8 × 12 × 6 Arc-Flat-Arc 0.206 .40 12.70.0109 3.16 158.8 88 8 × 12 × 8 Arc-Flat-Arc 0.206 .40 12.7 0.0109 3.55172.3 89 9 × 12 × 6 Arc-Flat-Arc 0.206 .30 12.7 0.0109 2.96 148.7 90 9 ×12 × 8 Arc-Flat-Arc 0.206 .30 12.7 0.0109 3.28 159.2

TABLE 6(b) SAE Fine Loading Volume to 12 inches H2O % Loading Element %Volume of Asymmetry Media % of Area of Element Pressure Drop of BaseFilter Volume (ft³) Base Filter (%) Required (ft²) Base Filter Flow Rate(cfm) 81 948 100.0 0.3333 100.0 0.00 76.2 100 636 82 1768 100.0 0.4444100.0 0.00 101.5 100 636 83 1311 138.3 0.3333 100.0 51.4 78.1 102.5 63684 2371 134.1 0.4444 100.0 51.4 104.2 102.7 636 85 1252 132.1 0.3333100.0 15.1 73.2 96.1 636 86 2258 127.7 0.4444 100.0 15.1 97.6 96.2 63687 1640 173.0 0.3333 100.0 18.9 113.0 148.3 636 88 2531 143.2 0.4444100.0 18.9 150.7 148.5 636 89 1696 178.9 0.3333 100.0 19.6 108.7 142.7636 90 2643 149.5 0.4444 100.0 19.6 145.0 142.9 636

TABLE 7(a) Element Flute Flute Plug Media Initial Pressure % of InitialSize Flute Type Height (J) Width/Height Length Thickness Drop (inchesPressure Drop of Element (inches) Comments and Size (inches) Ratio (mm)(inches) H2O) Base Filter 91 8 × 12 × 9  Standard B 0.103 2.45 12.70.0109 2.11 100 92 8 × 12 × 12 Standard B 0.103 2.45 12.7 0.0109 2.27100 93 8 × 12 × 9  Low Contact 0.103 2.60 12.7 0.0109 1.98 93.8 94 8 ×12 × 12 Low Contact 0.103 2.60 12.7 0.0109 2.13 93.8 95 8 × 12 × 9  LowContact 0.103 2.60 12.7 0.0109 2.19 103.8 96 8 × 12 × 12 Low Contact0.103 2.60 12.7 0.0109 2.31 101.8 97 8 × 12 × 9  Low Contact 0.103 2.6012.7 0.0109 2.63 124.6 98 8 × 12 × 12 Low Contact 0.103 2.60 12.7 0.01092.69 118.5 99 8 × 12 × 9  Arc-Flat-Arc 0.275 .30 12.7 0.0109 3.41 161.6100 8 × 12 × 12 Arc-Flat-Arc 0.275 .30 12.7 0.0109 3.98 175.3 101 8 × 12× 9  Arc-Flat-Arc 0.275 .30 12.7 0.0109 3.49 165.4 102 8 × 12 × 12Arc-Flat-Arc 0.275 .30 12.7 0.0109 4.02 177.1 103 8 × 12 × 9 Arc-Flat-Arc 0.275 .30 12.7 0.0109 3.58 169.7 104 8 × 12 × 12Arc-Flat-Arc 0.275 .30 12.7 0.0109 4.07 179.3

TABLE 7(b) SAE Fine Loading Volume to 12 inches H2O % Loading Element %Volume of Asymmetry Media % of Area of Element Pressure Drop of BaseFilter Volume (ft³) Base Filter (%) Required (ft²) Base Filter Flow Rate(cfm) 91 2222 100.0 0.5000 100.0 0.00 114.2 100 636 92 3600 100.0 0.6666100.0 0.00 152.3 100 636 93 2615 117.7 0.5000 100.0 0.00 114.7 100.4 63694 4126 114.6 0.6666 100.0 0.00 152.9 100.4 636 95 2934 132.0 0.5000100.0 49.1 116.1 101.7 636 96 4650 129.2 0.6666 100.0 49.1 154.8 101.6636 97 2988 134.5 0.5000 100.0 98.7 118.6 103.9 636 98 4666 129.6 0.6666100.0 98.7 158.1 103.8 636 99 2958 133.1 0.5000 100.0 0.00 162.3 142.1636 100 4164 115.7 0.6666 100.0 0.00 216.3 142.0 636 101 3126 140.70.5000 100.0 27.20 163.4 143.1 636 102 4370 121.4 0.6666 100.0 27.20217.8 143.0 636 103 3114 140.1 0.5000 100.0 44.10 163.9 143.5 636 1044256 118.2 0.6666 100.0 44.10 218.6 143.5 636

TABLE 8(a) Element Flute Flute Plug Media Initial Pressure % of InitialSize Flute Type Height (J) Width/Height Length Thickness Drop (inchesPressure Drop of Element inches) Comments and Size (inches) Ratio (mm)(inches) H2O) Base Filter 105 8 × 12 × 4 Standard B 0.103 2.45 12.70.0109 1.99 100 106 8 × 12 × 4 Standard B 0.103 2.45 7.0 0.0109 1.9899.5 107 8 × 12 × 4 Standard B 0.103 2.45 6.0 0.0109 1.98 99.5 108 8 ×12 × 4 Standard B 0.103 2.45 5.0 0.0109 1.97 99.0 109 8 × 12 × 4Standard B 0.103 2.45 4.0 0.0109 1.97 99.0 110 8 × 12 × 4 Low Contact0.103 2.50 7.0 0.0109 2.15 108.0 111 8 × 12 × 4 Low Contact 0.103 2.506.0 0.0109 2.15 108.0 112 8 × 12 × 4 Low Contact 0.103 2.50 5.0 0.01092.14 107.5 113 8 × 12 × 4 Low Contact 0.103 2.50 4.0 0.0109 2.14 107.5

TABLE 8(b) SAE Fine Loading % Volume Media to 12 inches % LoadingElement Volume of Asymmetry Required % of Area of Flow Element H2OPressure Drop of Base Filter Volume (ft³) Base Filter (%) (ft²) BaseFilter Rate (cfm) 105 314 100.0 0.2222 100.0 0.00 50.8 100.0 636 106 397126.4 0.2222 100.0 0.00 50.8 100.0 636 107 418 133.1 0.2222 100.0 0.0050.8 100.0 636 108 441 140.4 0.2222 100.0 0.00 50.8 100.0 636 109 465148.1 0.2222 100.0 0.00 50.8 101.0 636 110 575 183.1 0.2222 100.0 51.452.1 102.6 636 111 601 191.4 0.2222 100.0 51.4 52.1 102.6 636 112 634201.9 0.2222 100.0 51.4 52.1 102.6 636 113 666 212.1 0.2222 100.0 51.452.1 102.6 636

The above specification, examples and data provide a completedescription of the manufacture and use of the filtration media andfilter element of the invention. Since many embodiments of the inventioncan be made without departing from the spirit and scope of theinvention, the invention resides in the claims hereinafter appended.

We claim:
 1. A filtration media pack comprising: (a) a plurality of layers of single facer media wherein the layers of single facer media comprise a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet and having a flute length extending from a first face of the filtration media pack to a second face of the filtration media pack; (b) a first portion of the plurality of flutes being closed to unfiltered fluid flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered fluid flowing out of the second portion of the plurality of flutes so that fluid passing into one of the first face or the second face of the media pack and out the other of the first face or the second face of the media pack passes through media to provide filtration of the fluid; (c) the filtration media pack has an average flute length of greater than about 8 inches; (d) the filtration media pack has an average flute density of less than 34 flute/inch²; (e) the filtration media pack has an average media-cord percentage of greater than 6.3%, and (f) wherein the filtration media pack has a non-asymmetric volume arrangement so that a volume on one side of the media pack is not greater than a volume on the other side of the media pack by more than 10%.
 2. A filtration media pack according to claim 1, wherein the fluted sheet comprises repeating internal peaks facing toward the facing sheet and repeating external peaks facing away from the facing sheet and a pattern of at least one ridge extending along at least 50% of the flute length between an internal peak and an adjacent external peak.
 3. A filtration media pack according to claim 2, wherein the fluted sheet comprises at least two ridges along at least 50% of the flute length between an internal peak and an adjacent external peak.
 4. A filtration media pack according to claim 2, where at least two ridges are provided in a pattern between an internal peak and an adjacent external peak.
 5. A filtration media pack according to claim 1, wherein the filtration media pack has a flute width height ratio of greater than 2.5 of a flute height ratio of less than 0.4.
 6. A filtration media pack according to claim 1, wherein the filtration media pack has an average flute density of less than 25 flute/inch².
 7. A filtration media pack according to claim 1, wherein the filtration media pack has an average media-cord percentage of greater than 6.5%.
 8. A filter element comprising a filtration media pack according to claim 1 and a seal member extending around a periphery of the media pack.
 9. A method for manufacturing a filtration media pack comprising: (a) stacking or rolling layers of single facer media to form a filtration media pack, the plurality of layers of single facer media comprise: (i) a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet and the facing sheet and having a flute length extending from a first face of the filtration media pack to a second face of the filtration media pack; (ii) a first portion of the plurality of flutes being closed to unfiltered fluid flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered fluid flowing out of the second portion of the plurality of flutes so that fluid passing into one of the first face or the second face of the media pack and out the other of the first face or the second face of the media pack passes through media to provide filtration of the fluid; (iii) the plurality of flutes having an average flute length of less than 5 inches; and (iv) the filtration media pack exhibiting a flute density (p) of at least about 35.0 flute/inch² according to the formula: $\rho = \frac{\text{number~~of~~channels~~(open~~and~~closed)}}{2 \times z\text{-media~~pack~~cross~~sectional~~area}}$ wherein the number of channels is counted and the media cross sectional area is measured.
 10. A method according to claim 9, wherein the fluted sheet comprises repeating internal peaks facing toward the facing sheet and repeating external peaks facing away from the facing sheet and a pattern of at least one ridge extending along at least 50% of the flute length between an internal peak and an adjacent external peak.
 11. A method according to claim 10, wherein the fluted sheet comprises at least two ridges along at least 50% of the flute length between an internal peak and an adjacent external peak.
 12. A method according to claim 10, wherein at least two ridges are provided in a pattern between an internal peak and an adjacent external peak.
 13. A method according to claim 9, wherein the filtration media pack exhibits a flute density of at least about 40 flute/inch².
 14. A method according to claim 9, wherein the first portion of the plurality of flutes are sealed by a sealant bead and the second portion of the plurality of flutes are sealed by a sealant bead.
 15. A method according to claim 9, wherein the sealant bead sealing at least one of the first portion of the plurality of flutes or the second portion of the plurality of flutes have an average plug length of less than about 7 mm.
 16. A method according to claim 9, wherein the plurality of single facer media are provided in a coiled arrangement.
 17. A method according to claim 9, wherein a plurality of single facer media are provided in a stacked arrangement.
 18. A method according to claim 9, wherein the media pack has an asymmetric volume arrangement so that a volume on one side of the media pack is greater than a volume on another side of the media pack by at least 10%.
 19. A method according to claim 9, wherein the flute width height ratio is greater than 2.5.
 20. A method according to claim 9, wherein the flute width height ratio of less than 0.4. 